# Foam Filler



## Lightman (Aug 25, 2014)

I am running an experiment with EPS foam to see if I can make my own foam filler using scraps of broken foam and Glidden Gripper. If this works, sculpting mistakes can be fixed easily using the same material as the original. This is a work in progress...

If someone else knows of any other DIY foam fillers, please feel free to post links in this thread.

*The Process*

I have a piece of EPS white (beaded) foam where there is a broken notch that I would like to fill. The plan is to take the small scrap beads, mix them with Glidden Gripper, and use putty knife to spread it into the notch. Then wait 6 hours and see if the material is cuttable and sandable.










*Step 1 - Create Beads -Done*
I have taken old foam scraps and broken them down to their smallest aggregate component.. the bead and placed in a cup. Using a putty knife edge I continually chopped them down till just beads were left in cup

I found that spraying the foam pieces lightly with water helped contain the static clinginess of the foam beads. Not perfect... but definitively helped.

*Step 2 - Mix in Gripper - Done*
I took 1/2 teaspoon of Glidden Gripper and added it to the beads in cup and stirred thoroughly. Consistency is like large curd cottage cheese. I didn't want to use too much Glidden Gripper, but beads needed to be coated.










*Step 3 - Spread on Patch - Done*
Using a tongue depressor, I spread mixture into the notch carefully ensuring the underlayment foam received a fair amount of Glidden Gripper. As you can see in photo, the texture is very rough. I suppose a thin layer could have been painted on... but I went for simple to start.










*Step 4 - Drying - Done*
Wait 6 hours for it to dry (boring step)...this I where we are at today (7/7/15, 8 am, 90F, Edit: ~ 50% humidity).

After 1 hour, the surface was drying and as I pressed the patch with my finger, it was a bit "spongey" to touch.

After 2 hours...still very spongey and gripper oozes up past beads when pressed.

After 6 hours, patch is hardening up...slightly spongey to the touch. Minor oozing of gripper.

After 8.5 hours, patch is hard on surface, but still somewhat soft inside... time to cut it open (see next post)

After 24 hours, the new patch has firmed up. Cuts clean, but cross section has very thin layer of wet Gripper at boundary between orig foam and new patch. Rest of patch feels close to original foam. I will continue to let it dry.

After 28 hours, samples were dry. Move on to final step.

*Step 5 - Test Sculpt & Sand - Done*
At 8.5 hours I cut the "notch filled" area open and assessed the cross section to find Gripper was not fully dry (See next Post).

I cut new cross section after 24 hours and slice was clean. There is minor wetness at seam between new patch and old foam. Too early to do sanding test.

At 28 hours, Sculpting & sanding tests were performed successfully. Adhesion of patch to the original foam also proved successful. Texture of patch is a little rougher than original foam after sanding, but overall compression and strength seemed comparable to original foam. Recommend 48 hour dry time for thick patches.

See link to "Final Results" here...http://www.hauntforum.com/showpost.php?p=832163&postcount=8

Test is complete.


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## Lightman (Aug 25, 2014)

*Cutting Open New Patch (> 8 Hours Dry Time)*

After about 8.5 hours I cut the patch down the center to reveal the insides and determine why it is still somewhat soft. Reason...The gripper had not fully dried.










Here are the two sides split apart to reveal the thickness of the patch...









Here is the anatomy of the patch that is still drying....









I will let it dry over night and re-examine in the morning.


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## bobzilla (Nov 13, 2008)

Pretty ingenious Lightman!
I like how you think


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## RoxyBlue (Oct 6, 2008)

Sounds as if you might need to layer the patches so it dries better:jol: If this works, it will be useful for those times when you don't want divots as character.


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## Jaybo (Mar 2, 2009)

Well, you won't be able to carve the Gripper/Foam mix when it dries, so in that situation there are other items you could use for the same effect. 

Wood filler or joint compound can be used and sanded smooth.
Cut another piece a foam to roughly match the area you want to repair and glue it to the foam using Gorilla Glue after you sprayed both pieces with a mist of water, then sand the piece to match. Gorilla Glue is a chemical reaction that is activated by water, so less issues with drying time.
You could also just spray Great Stuff foam on the piece, then shape it. Although, the Great Stuff will be more dense than the white beaded stuff.


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## Lightman (Aug 25, 2014)

*Update 24 Hours Later*

Patch has firmed up nicely, but new cross section reveals a thin layer of wet Gripper at boundary of orig foam and new patch. Rest of patch has dried and has similar "spongey-ness" as the original foam.

When cutting new cross section, patch sliced cleanly.

Note: We are going through monsoon season in Tucson so humidity is unusually high (typically > 50%). Today, drier air is coming in and humidity will drop to 40%. Normally, we are below 30% where "air drying" products are very quick to dry.

Will continue to let it dry before attempting sanding.


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## discozombie (Jun 21, 2012)

I use a similar method but use foam scrap and liquid nails. Not as easy to shape since it doesn't sand that well. Im gonna try the gripper method.


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## Lightman (Aug 25, 2014)

*Final Results*

After drying the EPS Foam patched sample(s) 28 hours with the last 4 hours in 15% humidity climate at 95F, I decided to perform the final steps of sculpting and sanding of the patch.

Results: Overall, the patch worked with great adhesion as well as sandability and sculptability. The coarse nature of the aggregate made up of loose beads and Glidden Gripper did results in some "pitted" looking surface characteristics. The patch material acted similarly in handling and compression as the original foam, just a coarser texture. During Sculpting I noticed some wet Gripper in places... so more drying time is still needed... I assume 48 hours, depending on thickness of patch.

*Details of Final Step*

I broke the test up into 3 parts 1) Sanding, 2) Sculpting, 3) Adhesion.

Here is sample before sanding, sculpting and adhesion tests....









Part 1 - Sanding

I took one of the samples and sanded it with 80 Grit sand paper. I sanded both the original and patch areas together for a fair comparison. The patch did shimmy a bit while sanding, but then calmed to a normal feel. The original smoothed off right away. As sanding progressed, the two materials began to sand as one. Here is final 80 grit sanded sample...










I then sanded the sample with 220 Grit sand paper for a finer surface. Again I sanded both new and old materials together. They both felt the same as sanding progressed. Here is final 220 Grit sanded sample...










Step 2 - Sculpting

Using another sample, I used a new OLFA 9mm blade to sculpt out a few shavings from both the new patch and the original foam. Due to limitations of # of photos in a post, I cant show you the original sample before cutting, but refer to photo at top of this post for representative sample.

Cutting felt the same for both types of the materials. I did notice a few beads broke free, but the majority of the beads held tight as they were being sliced and sculpted. The photo below depicts the two regions as well as a sample of the shavings. (Study the shaving at the bottom of photo... it shows the cut beads and the Gripper in between beads)










Step 3 - Adhesion

I then took one of the samples and tugged at the patch to see how well it adhered to the original foam. It stuck very well and the original foam tore before the patch. See the results in the photo here...










*Conclusions*

The DIY patch process using separated EPS beads and Glidden Gripper was successful in sanding / sculpting once patch thoroughly dried. Adhesion of the patch to the original foam was also successful.

Drying time appears to be a bit excessive (48 hours) but can be reduced if the patch is layered in in thinner sections, allow it to dry before applying next layer.

Texture of the patch is coarser than the original EPS foam since the uncompressed beads are not "Squashed" into each other as the Gripper dries. Sanding improves the smoothness, but doesn't exactly match original foam properties.

Bead Adhesion to each other was formidable. The individual beads did full apart with the same force whether it was the original foam or patch. So the aggregate process does work and can be possibly applied with other glues/adhesives.

The goal here was to refill a sculpting mistake with material similar to the original foam so as to minimize effort to re-sand and re-sculpt. I believe that goal was met... but the final characteristics of the patch are not 100% the same as original foam. That said... one can go a long way using this technique, if patient enough with long drying time.

*Future Considerations*

1) Use other adhesive in aggregate to see if drying time can be reduced
2) Press patch into place with plastic to force the beads closer during drying (counter productive to air drying beads though)
3) Consider filling missing bead gaps with wood filler as final step
4) Employ thinner patch layers to allow faster drying times... then add another layer...etc... building up patch.


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## Lightman (Aug 25, 2014)

bobzilla said:


> Pretty ingenious Lightman!
> I like how you think


Thanks Bob. I am humbled by your kind words.


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## Lightman (Aug 25, 2014)

RoxyBlue said:


> Sounds as if you might need to layer the patches so it dries better:jol: If this works, it will be useful for those times when you don't want divots as character.


You are spot on! Thin layers appear to be the best approach...giving them time to dry.


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## Lightman (Aug 25, 2014)

Jaybo said:


> Wood filler or joint compound can be used and sanded smooth.
> Cut another piece a foam to roughly match the area you want to repair and glue it to the foam using Gorilla Glue after you sprayed both pieces with a mist of water, then sand the piece to match. Gorilla Glue is a chemical reaction that is activated by water, so less issues with drying time.
> You could also just spray Great Stuff foam on the piece, then shape it. Although, the Great Stuff will be more dense than the white beaded stuff.


Good list of classic filling techniques. In the end, all these processes have their place in our toolkit of foam work.

Thanks for listing them.


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## Lightman (Aug 25, 2014)

discozombie said:


> I use a similar method but use foam scrap and liquid nails. Not as easy to shape since it doesn't sand that well. Im gonna try the gripper method.


Never thought of using liquid nails...good to know about your results. This begs the question...how about using Locktite's foam adhesive as the aggregate filler?

The ideal adhesive for these patches is strong adhesion with "plyable" attributes...for some give and take when dry...IMHO.


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