Idea: DIY foam filling

[Slitch]

Hi guys!
I’ve been reading up on these forums for about a year but had nothing to contribute, until now! I want to try something, but I need your help.

When I started playing again I almost became obsessed with customizing. Love how simple things change your game. Last year I got a nasty case of wrist tendonitis and TE so I’ve been thinking about reducing the possibility of it returning. I've allready bought a Fischer Magnetic Tour SL but i want to try and make my old frames more suitable.
I’ve been reading up on a lot of articles and apparently foam filled rackets damp a lot of unwanted vibrations. These claims are supported by research found in the patent US 4983242:

‘[00038] A tennis racket frame made in accordance with the present invention was tested against a Prince graphite Series 110 tennis racket for vibration dampening characteristics. The control sample racket frame had an all graphite tubular shell with a nominal wall thickness of 0.065" and included a foam core. The sandwich construction test racket frame was a hollow tubular configuration, without a foam core, made in the same mold as the
control sample frame’
‘[00039] Each racket was, sequentially, placed in a test rig and clamped at the top of the tail section (50 cm from the tip). An accelerometer was placed on the tip. Vibration was initiated by directing a tennis ball at the center of the strings. The vibration amplitude and frequencies of each racket were measured on an Ono Sokki CF300 portable FFT analyzer.’
‘[00040] FIGS. 5a and 5b show the vibration amplitudes over time for the two rackets. As indicated in the charts in FIGS. 5a and 5b, after a period of 0.4 seconds, the ratio of vibration in the sandwich construction racket was 0.206 of the original vibration, whereas the vibration in the control racket was 0.509. Thus, a racket construction in accordance with the invention dampened vibration twice as well as in the control racket.’

The idea is simple. You fill the racket with polyurethane and it damps, right? Such an undertaking could ruin the frame. Lucky I’ve found some old frames in our garage which might be suitable for experimenting. First of all I’ve found a beautiful old Fischer Vacuum Pro 98 (blue metallic). Sadly though, my dad tried the bounce test when he lost so it’s cracked. Luckily this is perfect for our experiment. I can fill it up with PU foam and saw it in half to check if the foam reaches all desires places. Got an old junior frame I hated so I’m going to enjoy cutting that one up. All tough that may sound fun, little bit more research is needed before I ruin everything.

I’ve found some threads on TT, but nothing really concrete turned up. I’ve found Anirut solution which is interesting. Sadly though, no progress has been made.

I then looked at the racquet companies who fill their rackets with foam. First of all I looked at Donnay but nothing interesting came up. Then I looked at Angell and I found this:

MD Foam Core
Every frame is filled with mid density PU foam, suppressing vibration and helping to control our tight manufacturing tolerances by internally controling weight distribution.

This gave me two ideas. First, medium density foam is used:
Medium density foam tends to fall between the high 1.8 lbs/ft3 range to just under a 3lb/ft3 range. It is a closed-cell foam.
It may be referred to as an H series foam with appropriate numbers denoting its firmness, such as H21 (soft), H30 (medium) and H45 (firm). If it encounters everyday use the lifespan for the foam is typically 4 to 6 years.

Second, it’s based on polyurethane. Now I can narrow my search. I first thought of Foam spray cans. This looked perfect, but I don’t think it would work because the polyurethane expands to fast. Then I found a thread about guys repairing their wakeboards with PU foam. They just mix it themselves and inject it using syringes and it cures a lot slower. I thought I needed a little more research.
I quickly found a patent, US 4340226, which explains a lot. Here are some parts interesting parts:

‘A hollow injection moulded thermoplastics games racket frame comprising a head (21) and a shaft (20), the head (21) having integrally-formed internal supports (25) containing the stringing holes (23) and the moulding being polyurethane foam-filled. The foam filling is provided in two parts, a lighter filling (32) for the head and a denser filling (33) for the shaft.’


‘[00010] The head filling may be of flexible or rigid polyurethane foam (the latter being preferred) and may extend, if desired, partway along the shaft up to a limit of the commencement of the handle portion of the shaft.’

‘[00011] The invention provides a convenient and advantageous way of obtaining racket frames having particular weight and balance properties. Thus it will be appreciated that the use of two foam fillings of different densities enables racket frames to be fabricated having a relatively wide range of balance characteristics at any given weight.’

‘[00012] It may be found convenient to use the same polyurethane foam formulatIon for the head filling and for the shaft filling. The required difference in final foam density can then be readily achieved by an appropriate calculation based on the weight of foam precursors used and the volume to be filled.’

‘[00013] Preferred polyurethane foams to be used in the invention are obtained from the reaction of a diisocyanate, e.g. methylene diisocyanate or tolylene diisocyanate, with a polyol, e.g. propylene glycol. The desired densities of the final foam fillings may be achieved, for example, by using quantities of precursors that would give a lighter than desired density if allowed to rise freely rather than being constrained within the volume of the hollow moulded frame. Thus, for example, the foam used for the head filling may have a free-rise density of 0.03 to 0.04 g/c.c. and the foam used for the shaft filling may have a free-rise density of 0.20 to 0.22 g/c.c. By accurate metering of the precursors and by constraining the foam, as it is generated, within certain volumetric limits it is possible to achieve substantially uniform foam quality without significant voids.’

I then looked up how to mix PU and how long it would take to foam:

1. Set the temperature in the area you are working in to roughly 75 degrees F. Leave the foam and mold in the room for at least 24 hours to allow them to take on the ambient temperature. If the floor is not insulated, keep the mold on a work table off of the floor.

2. Measure the "A" and "B" ratios exactly, according to the ratios listed on the containers. Most soft foam combines at a ratio of 28:72. Most rigid foam combines at a one to one ratio. Measure the ratios with a scale to within one gram of accuracy. Over- or under-mixing will interfere with the foam's ability to cure.

3. Mix the polyurethane quickly and thoroughly. Set a timer. You have around 45 seconds to mix before the foam starts to expand. Mix the foam in its mixing container for 25 seconds. For the best results, use a drill mixer set to high speed. You will then have roughly 20 seconds to pour the polyurethane into the mold. If you do not mix thoroughly and pour quickly, the foam may not cure or expand properly.

4. Mix the liquid in the mold after you pour it, within the 45-second mix time described in Step 3. Stop stirring when the 45 seconds are up.

5. Allow the foam ample time to cure. The foam will expand for roughly five minutes. It will need another 15 minutes to cure and fully harden. If the temperature is lower than 75 degrees F., the cure time will be longer. Allow the foam to cure for as long as 30 minutes if temperatures are around 65 degrees F.

http://www.ehow.com/how_10054995_cure-polyurethane-foam.html

My thoughts:

1. The creator uses two kinds of PU foam because they construct the racket head & throat in one piece and later mold the handle using PU, therefore needing a denser and harder PU foam. This is not relevant because I don’t want to make a handle as an integral part of the core.

2. Medium Density PU foam is between 1.8 lbs/ft3 to just under a 3lb/ft3 which equals 0,0288g/cc to 0,0481g/cc. This correlates with the data in the patent US 4340226. H35 should be perfect.

3. The volume of the racket should be calculated. This can be down by filling the racket with water and emptying it in a measuring cup. This will also clear the inside of any dirt which could interfere with the PU foam. Water can influence the PU mixture. But It could be cured by drying with a hair dryer and then placing it in a rice bag.

4. The PU needs to be poured into 1 shaft so air can escape. I don’t know if the rise time will influence the dispersion of the foam inside the frame. I assume we need foam with a slow rise time, so every drop can reach between the grommets. The video’s I’ve seen lead me to believe that I won’t have much time once it’s mixed. Within 20 seconds it has already doubled in size. Apparently it only stays liquid for 45 seconds. I will not have much time to pour.

5. The balance can be corrected by drilling in the PU in the handle and inserting lead. I don’t know if silicon will bind to the PU.

6. I need to at least try it. It could be great for people with chronic tendon issues who are on a low budget, or for people who like to experiment.

All help is welcome. If anybody wants to help or, know someone like a professional/chemist who would be willing to help, that would be much apreciated.

Thank you for reading my long post.

 

[Slitch]

About me:
I’m a 25 year old student living in the Netherlands. I love sports and enjoy football (the sport where you kick the ball with your foot and now throw it), fitness, skiing and off course tennis.

I started playing tennis when I was 3 and quickly I was known as the little Agassi of my club. I played on a full court when I was 6 so I was way above most of my age classmates. All tournaments were on small court. Got a crappy racket and even more worse strings. My dad got a nasty case of TE and stopped playing. That’s when tennis started to get boring slowly. Started playing football and eventually stopped playing tennis when I was 11. When I was 14 I bought a hollow Fischer Beat Pro Titanium with a flex of 66 to relive old moments. Got a real serious knee injury and sheered a tendon in my shoulder due to a failed front flip while skiing backcountry

Last year I started playing some tennis again for the first time in 12 years. Immediately fell in love and started playing 9-15 hours a week. I hated the HH balance and slapped on 30 grams of lead under the handle, increased the grip size. Got some WC SS in and absolutely loved it. Bought a secondhand mgpp from a forum member (don’t know his nickname). Got it strung up to tightly with WC TT. Put in about 15g of silicone and a Tourna. Don’t love the grip shape, but It’s better than the old round Fischer grip.
Played with the poly to long with too much wrist movement and tight gripping and as a result got a nasty case of Wrist tendonitis and TE. Loved the sport so much that I kept playing with wrist band from zamst which helped a lot. Too much actually because I kept playing. Then I took a break for about 2 months to up my physique and recover. Got it strung up with WC MB and B5E hybrid. Great to play but my wrist hates it.
So this year I bought a used Magnetic Tour SL real cheap. Little bit more flex and bigger headsize. Strung it op with WC Xplosiv.
My seasons starts in two weeks some I'm eager to get back out there

 

[Lefty78]

Racquets which are foam filled at the factory have this process performed before the holes are drilled and the grommets are installed.

In your case, you will risk foam seeping out through the holes. I doubt the grommets fit tightly enough to prevent this as the foam creates a lot of pressure as it expands.

If you're set on trying it, I think you're on the right track starting with an old, cracked frame.

Best of luck to you

 

[rlau]

What if you just fill the handle with foam? Put some cotton wads down the handle to avoid foam seeping down in the frame and then inject the foam into the chambers. Then see what what difference it makes.

 

[Slitch]

Racquets which are foam filled at the factory have this process performed before the holes are drilled and the grommets are installed.

In your case, you will risk foam seeping out through the holes. I doubt the grommets fit tightly enough to prevent this as the foam creates a lot of pressure as it expands.

If you're set on trying it, I think you're on the right track starting with an old, cracked frame.

Best of luck to you

Apparently according to the patent filed, the grommet holes are closed as they contribute to the structural integrity of the frame.

 

[Slitch]

What if you just fill the handle with foam? Put some cotton wads down the handle to avoid foam seeping down in the frame and then inject the foam into the chambers. Then see what what difference it makes.

Thats is possible, though the dampning apparantly occurs most in the head. It is interesting as it would not alter the balance much but might give a little bit more dampnening. Definitly a solution, but not the optimal solution I would like to achieve.

 

[yonexRx32]

Apparently according to the patent filed, the grommet holes are closed as they contribute to the structural integrity of the frame.

The method described in the patent applies to injection molded frames, with very particular grommet holes. There is no drilling involved. There are only a handful of such frames. Regular rackets are build through a thermoset process, then drilled.

 

[sureshs]

The method described in the patent applies to injection molded frames, with very particular grommet holes. There is no drilling involved. There are only a handful of such frames. Regular rackets are build through a thermoset process, then drilled.

In other words, the foam will ooze out through the string holes, right?

 

[tennis ratchet]

here in the us we have this stuff called foam backing rod at home depot

http://tinyurl.com/bcdnuzs

you might try putting some of this down the handle, at least you'll be able to take it out without ruining the racket. i have foam in the handle of my blx 98... recently put some blu tac (in a baggie) in the handle of my tecnifibre racket, but thought about using foam rod, since i didn't want to ruin my racket like the sore loser i read about on tw.

 

[SFrazeur]

I think you will this interesting: http://tt.tennis-warehouse.com/showpost.php?p=1113290&postcount=355 http://tt.tennis-warehouse.com/showpost.php?p=1113298&postcount=353
Foam pellets.

-SF

 

[Hi I'm Ray]

^^ Some of the old Fischers have the handle already filled with foam pellets, it might be difficult to get those into the hoop though.

OP: One of the problems with filling the hoop with foam is that it can add a significant amount of weight/SW, unless the frame starts off low SW. I removed the foam from the hoop & handle of an old heavy racket and a it made a very noticeably reduction in weight/SW.

 

[anirut]

Hi Slitch,

Nice to see a another crack pot trying crazy things. Hey, I mean it in a good way.

You've got it all correct in your first post that you need to calculate so and so and so. I'm not going to teach you how do this or that -- I'm not a qualified tech. Rather, I'm a qualified crack pot.

OK, I see that you mentioned in your post: "Sadly though, no progress has been made." about the filling rackets with foam pellets.

I don't know if I can call it a progress. For whichever racket that I want a "less-hollow and softer" feel and adding just a few grams to the racket, I STILL USE this method. It's easy to do, can be easily undone.

Recently I just filled up my Dunlop Hotmelt 100 - a 90" head stick, 20 mm beam - and it added less than 3 grams. Now, if the added weight were only in the hoop that would've added a lot of SW, but not this case, as the pellets are more in the shaft and handle due to the larger cavity. The racket now feel noticeably firmer and softer. Not just me feeling it, but my hitting partners as well.

I'm not saying my method is best, but, as I said, it's easy and undo-able. You could try this first and see if it works for you.

I have a friend working a foam injection factory and she told me to get my rackets there. I thought about it but don't wanna ruin my rackets. I have some rackets that I just hated but I could still sell them stock for a decent price. If I were to use them as test platforms I wouldn't be able to sell them, and that's money lost.

Anyhow, I look forward to your experiment - and I ENCOURGE it. This will certainly bring knowledge to the tennis circle.

Until I can get a few rackets of the same model for dead cheap price ... until then ...

 

[Tamiya]

been thinking same myself, how to fill frame with a foaming liquid that cures hard

imho a space-invading liquid foam is different to stuffing with styro beads;
the cured foam sets hard & adheres to the inside of the tube/s.
It'll probably add stiffness.

was chopping a W PS the other day (too curious what was inside "PWS")
and can confirm if you wanted to fill the frame, you'd need to remove
grommets & sealup all the holes with tape.
Redrill them after foam cured.

other odd issue... looking up several graphite butts there seems to
be a layer of plastic inside each tube. Dunno if this is to prevent sticking
to the mold at the factory or maybe they pump it up to firm the weave.


Definitely... founding member of the crackpot society :twisted:

 

[Tamiya]

Until I can get a few rackets of the same model for dead cheap price ... until then ...

originally was aiming for multiples of "goodname" racquets for modding


now thinking... maybe should try with "lesser" &/or generic brandnames,
after all won't it be easier to "improve" them rather than start off high?

recently i see some china no-name frames going for $4ea by the 1000...

 

[Slitch]

The method described in the patent applies to injection molded frames, with very particular grommet holes. There is no drilling involved. There are only a handful of such frames. Regular rackets are build through a thermoset process, then drilled.

Well I checked if the grommet holes are open on the Fischer, and you're right. This is an advantage because the air in the hoop could escape. That way I can fill the hoop faster by pouring it in both shafts. I could just carefully drill the PU out of the grommet holes.

^^ Some of the old Fischers have the handle already filled with foam pellets, it might be difficult to get those into the hoop though.

OP: One of the problems with filling the hoop with foam is that it can add a significant amount of weight/SW, unless the frame starts off low SW. I removed the foam from the hoop & handle of an old heavy racket and a it made a very noticeably reduction in weight/SW.

Yeah found that out this morning, the pallet is made of dense PU.
Initially I was worried about the swingweight. According to my rough calculations we only need about 5, maybe 10 grams in the hoop. That maybe the right amount for lighter frames.

Hi Slitch,

Nice to see a another crack pot trying crazy things. Hey, I mean it in a good way.

You've got it all correct in your first post that you need to calculate so and so and so. I'm not going to teach you how do this or that -- I'm not a qualified tech. Rather, I'm a qualified crack pot.

OK, I see that you mentioned in your post: "Sadly though, no progress has been made." about the filling rackets with foam pellets.

I don't know if I can call it a progress. For whichever racket that I want a "less-hollow and softer" feel and adding just a few grams to the racket, I STILL USE this method. It's easy to do, can be easily undone.

Recently I just filled up my Dunlop Hotmelt 100 - a 90" head stick, 20 mm beam - and it added less than 3 grams. Now, if the added weight were only in the hoop that would've added a lot of SW, but not this case, as the pellets are more in the shaft and handle due to the larger cavity. The racket now feel noticeably firmer and softer. Not just me feeling it, but my hitting partners as well.

I'm not saying my method is best, but, as I said, it's easy and undo-able. You could try this first and see if it works for you.

I have a friend working a foam injection factory and she told me to get my rackets there. I thought about it but don't wanna ruin my rackets. I have some rackets that I just hated but I could still sell them stock for a decent price. If I were to use them as test platforms I wouldn't be able to sell them, and that's money lost.

Anyhow, I look forward to your experiment - and I ENCOURGE it. This will certainly bring knowledge to the tennis circle.

Until I can get a few rackets of the same model for dead cheap price ... until then ...

The pellets are a great idea, I just want to go a bit further and have some fun. If my experiment doesn't succeed I will definitely try the pallets!

Why don't you just take a look in a thrift store and pick up a racket for a few bucks and give it a try? If your friend knows she knows her stuff, give it a try!

been thinking same myself, how to fill frame with a foaming liquid that cures hard

imho a space-invading liquid foam is different to stuffing with styro beads;
the cured foam sets hard & adheres to the inside of the tube/s.
It'll probably add stiffness.

was chopping a W PS the other day (too curious what was inside "PWS")
and can confirm if you wanted to fill the frame, you'd need to remove
grommets & sealup all the holes with tape.
Redrill them after foam cured.

other odd issue... looking up several graphite butts there seems to
be a layer of plastic inside each tube. Dunno if this is to prevent sticking
to the mold at the factory or maybe they pump it up to firm the weave.


Definitely... founding member of the crackpot society :twisted:

Well I don't know if the racket becomes stiffer, but I expect it to be firmer, more solid when struck. The beads are the basic principle, just less dense with more air between the 'cells'.

Well I thought about it, and the grommets definitely need to be removed. I thought about inserting nails in the holes. If the foam is cured I could try and gently heat the nails and pull them out.


Sadly though, I can't try it yet because the temperature in my garage is to low to create the right PU.

 

[sundaypunch]

In a racquet designed to be hollow, the main problem if you were able to inject the foam in the head will be the added weight. I would only experiment on a racquet that is much lighter than what you like.

 

[pug]

I filled my 2012 Babolat Pure Drive Plus with foam. It came out 12.1 ounce / 341 grams and 7 pts head light with a leather grip and gut / poly hybrid string job.

Very solid and dampened but still maintains the pure drive qualities that I like.

Damaged the paint but I learned a lot and I can do better next time.

 

[anirut]

Nice work, pug!

 

[sundaypunch]

I filled my 2012 Babolat Pure Drive Plus with foam. It came out 12.1 ounce / 341 grams and 7 pts head light with a leather grip and gut / poly hybrid string job.

Very solid and dampened but still maintains the pure drive qualities that I like.

Damaged the paint but I learned a lot and I can do better next time.

Did you measure the before/after weight? I'm curious how much weight the foam added.

I had posted a thread asking about adding silicone & lead to a PD Lite but it has been crickets chirping over there....

http://tt.tennis-warehouse.com/showthread.php?t=457442

 

[Slitch]

Looks great pug, thumbs up for trying it!
What kind of PU did you use? Did a lot of foam come out of the grommet holes? Looking at the standard specs of the PD+, the foam added about 15 g?

 

[Hi I'm Ray]

Well I checked if the grommet holes are open on the Fischer, and you're right. This is an advantage because the air in the hoop could escape. That way I can fill the hoop faster by pouring it in both shafts. I could just carefully drill the PU out of the grommet holes.

Yeah found that out this morning, the pallet is made of dense PU.
Initially I was worried about the swingweight. According to my rough calculations we only need about 5, maybe 10 grams in the hoop. That maybe the right amount for lighter frames.

Well I thought about it, and the grommets definitely need to be removed. I thought about inserting nails in the holes. If the foam is cured I could try and gently heat the nails and pull them out.

You can prevent the foam from sticking to the grommets, nails, the surface of the racket (where the foam oozes out), etc., by rubbing some candle wax on those surfaces. I've done this with various glues including PU glue. If you have a lot of surfaces to cover it will go faster if you can get the wax onto a paper towel or rag first.

If the PU foam you use is soft enough you can just push a drill bit through and give it a quick twist by hand, if you are worried you might accidentally widen the holes with an electric drill.

 

[Tamiya]

if you care about protecting paint finish you can also try
latex liquid paint mask.

 

[MikeA]

Boat shops sell a two part expanding foam for flotation that can be poured into tight spaces. I would tape the holes and go for it, the expanding foam will push the tape out and then drill the grommets after.

 

[Slitch]

Boat shops sell a two part expanding foam for flotation that can be poured into tight spaces. I would tape the holes and go for it, the expanding foam will push the tape out and then drill the grommets after.

Yeah, water sport shops sell the same stuff and it comes cheap. Apparently the 35kg/m3 foam expands slowly so I would have enough time to pour it all the way down. The expansion rate is 25 times the normal volume so I would need no more than 20ml.
Ray gave me great trip so I'm less worried about ruining the paint job.

 

[mykoh]

a foam-filled PD sounds absolutely badazz.. cant wait to see what you end up with Slitch.

 

[Tamiya]

any progress since? :-?

 

[Slitch]

The temperature is too low to get the right chemical reaction. Next week the temperature should be 20 degrees celsius, so look back in about 7-10 days. I'm ordering all the stuff this week so I'll be set for my experiment. Slighty pulled a tendon in my ellbow playing football so I have all the time in the world...

 

[Slitch]

Well I was wrong... working temperatures should be at least 80 degrees F / 26 degrees C. I don't expect the temperatures to rise that quickly. I'll have to find a room I can use and put a heater in. That way I can assure the proper chemical reaction.

 

[Shtangy]

Hi guys!
I’ve been reading up on these forums for about a year but had nothing to contribute, until now! I want to try something, but I need your help.

When I started playing again I almost became obsessed with customizing. Love how simple things change your game. Last year I got a nasty case of wrist tendonitis and TE so I’ve been thinking about reducing the possibility of it returning. I've allready bought a Fischer Magnetic Tour SL but i want to try and make my old frames more suitable.
I’ve been reading up on a lot of articles and apparently foam filled rackets damp a lot of unwanted vibrations. These claims are supported by research found in the patent US 4983242:


The idea is simple. You fill the racket with polyurethane and it damps, right? Such an undertaking could ruin the frame. Lucky I’ve found some old frames in our garage which might be suitable for experimenting. First of all I’ve found a beautiful old Fischer Vacuum Pro 98 (blue metallic). Sadly though, my dad tried the bounce test when he lost so it’s cracked. Luckily this is perfect for our experiment. I can fill it up with PU foam and saw it in half to check if the foam reaches all desires places. Got an old junior frame I hated so I’m going to enjoy cutting that one up. All tough that may sound fun, little bit more research is needed before I ruin everything.

I’ve found some threads on TT, but nothing really concrete turned up. I’ve found Anirut solution which is interesting. Sadly though, no progress has been made.

I then looked at the racquet companies who fill their rackets with foam. First of all I looked at Donnay but nothing interesting came up. Then I looked at Angell and I found this:


This gave me two ideas. First, medium density foam is used:
Medium density foam tends to fall between the high 1.8 lbs/ft3 range to just under a 3lb/ft3 range. It is a closed-cell foam.
It may be referred to as an H series foam with appropriate numbers denoting its firmness, such as H21 (soft), H30 (medium) and H45 (firm). If it encounters everyday use the lifespan for the foam is typically 4 to 6 years.

Second, it’s based on polyurethane. Now I can narrow my search. I first thought of Foam spray cans. This looked perfect, but I don’t think it would work because the polyurethane expands to fast. Then I found a thread about guys repairing their wakeboards with PU foam. They just mix it themselves and inject it using syringes and it cures a lot slower. I thought I needed a little more research.
I quickly found a patent, US 4340226, which explains a lot. Here are some parts interesting parts:


I then looked up how to mix PU and how long it would take to foam:


My thoughts:

1. The creator uses two kinds of PU foam because they construct the racket head & throat in one piece and later mold the handle using PU, therefore needing a denser and harder PU foam. This is not relevant because I don’t want to make a handle as an integral part of the core.

2. Medium Density PU foam is between 1.8 lbs/ft3 to just under a 3lb/ft3 which equals 0,0288g/cc to 0,0481g/cc. This correlates with the data in the patent US 4340226. H35 should be perfect.

3. The volume of the racket should be calculated. This can be down by filling the racket with water and emptying it in a measuring cup. This will also clear the inside of any dirt which could interfere with the PU foam. Water can influence the PU mixture. But It could be cured by drying with a hair dryer and then placing it in a rice bag.

4. The PU needs to be poured into 1 shaft so air can escape. I don’t know if the rise time will influence the dispersion of the foam inside the frame. I assume we need foam with a slow rise time, so every drop can reach between the grommets. The video’s I’ve seen lead me to believe that I won’t have much time once it’s mixed. Within 20 seconds it has already doubled in size. Apparently it only stays liquid for 45 seconds. I will not have much time to pour.

5. The balance can be corrected by drilling in the PU in the handle and inserting lead. I don’t know if silicon will bind to the PU.

6. I need to at least try it. It could be great for people with chronic tendon issues who are on a low budget, or for people who like to experiment.

All help is welcome. If anybody wants to help or, know someone like a professional/chemist who would be willing to help, that would be much apreciated.

Thank you for reading my long post.

Hey mate im a pro tennis player from Australia
I would go as far as saying customization is essential for high level tennis

I agree with you when I red the Angell racket post about how they have phome in there handle I wondered if I could do it as well

Have you hit with it

Can you review this for me please and thanks my guy

 

[Zoolander]

Hey mate im a pro tennis player from Australia
I would go as far as saying customization is essential for high level tennis

I agree with you when I red the Angell racket post about how they have phome in there handle I wondered if I could do it as well

Have you hit with it

Can you review this for me please and thanks my guy

OP is long gone i think. Have tried the foam in a can to fill up the handle/throat but its too dense and really deadened the feel too much for my liking. Foam pellets/bean bag balls were much better and made a noticeable difference while adding only a few grams weight, but they will eventually make their way into the hoop and get stuck and rattle around annoyingly. I would push a thin plastic bag down the handle and fill it up so they couldnt escape any further, with a bit of silicone or bluetac in the end...

 

[anirut]

@Zoolander
To avoid pellets rattling in the hoop, you have to be very patient when filling it. I kept tapping the racket to allow the pellets to fall in deep and just kept filling until they won't move down further.

Close the racket end and take it out for some serious swings to help "push" the pellets further. Believe it or not, once the end is opened, there's a void. So, I filled it up more and use a rather big foam piece to push down really hard and then close the butt cap. No rattles!