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PMF on foam door squishy

PostPosted: Sun Jun 26, 2016 12:59 pm
by nagnificent
Hi there everyone, please be patient with my new ignorant self. I'm unsure about how to make posts or I should say where to put them. I'm assuming since this is a new topic for my trailer, then I should start another post for it. Please correct me if I am wrong. :NC

I decided to make a foam door, for cost efficiency as well as light weight. I cut my door out and made it so fit into the wall in a way that would help with water proofing, cut the door handle and put a non opening plexiglass window. When I had it ready for applying pmf I thought I was a superhero, oh so proud of myself. :lol:

OHoh, well it didn't work out as well as I thought. I read how hospital sheets work well and make a hard solid finish, so I decided to use the sheets with the pmf methods described on here. I sanded the door and cleaned it well, applied my glue with the sheets. It was a bit difficult to smooth it out around the rounded edges and where I notched it to fit into the wall. I did get it done, but it stayed squishy way past the time that it should be dried.

Bubbles decided to come and visit, and overstayed her welcome. There were quite a few and I initially did the steam iron thing. No such luck, only a few responded well to this, but a large amt of them remained pretty pronounced. In my frustration I cut them open and injected glue. It has been sitting for a week now while I tinkered with other things, but it seems to have worked at quick glance.

It is still squishy and I am unsure about what to do to make it solid. Would it work if I painted on canvas over what is already there. I'm thinking paint over paint, like painting the canvas onto wood. Or would it work better if I glue the canvas down and then paint over, how we do over foam. This is how it looks now with the ugliest paint color I could possibly find, the brown one. The yellow pic just the glue before painted.

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Re: PMF on foam door squishy

PostPosted: Mon Jun 27, 2016 6:27 am
by GPW
Try putting it out in the Sun .... ;) Could have been the hospital sheets ?? Sounds like they blocked the glue (?) from drying ... and may explain the bubbling ... :thinking:

Re: PMF on foam door squishy

PostPosted: Mon Jun 27, 2016 2:09 pm
by nagnificent
GPW wrote:Try putting it out in the Sun .... ;) Could have been the hospital sheets ?? Sounds like they blocked the glue (?) from drying ... and may explain the bubbling ... :thinking:



Thank u so much for responding, I really appreciate it.

The door has been out in the sun, and I did hope that would do something. At this point will covering it again but with canvas will that firm it up, I'm really not sure what to do at this point. Should I try to take it all off and start over. Or God forbid start another door all over again? :cry:

Re: PMF on foam door squishy

PostPosted: Mon Jun 27, 2016 3:59 pm
by GPW
If the old covering is not working and is still not dry something must be wrong eh ??? Try removing the old skin (sheets ) and see what’s going on ... :thinking: This is very strange and I don’t think any of has heard of this happening before ... :NC

Re: PMF on foam door squishy

PostPosted: Mon Jun 27, 2016 6:34 pm
by tac422
What kind of glue did you use ?

Re: PMF on foam door squishy

PostPosted: Mon Jun 27, 2016 6:51 pm
by mikeschn
Hospital sheets are not very porous. I'd rip off the sheet and redo it with some cheap Home Depot canvas and TBII

:thumbsup:


Mike...

Re: PMF on foam door squishy

PostPosted: Mon Jun 27, 2016 7:18 pm
by nagnificent
Once again, thank you so much for responding.

I used TBII and free hospital sheets. I guess its true u get what u pay for huh? :) What a bummer, I have about five more free sheets I was gonna use for my trailer, but guess this will put a stop to that huh? :)

GPW wrote:This is very strange and I don’t think any of has heard of this happening before ...


I know, from everything that I have read the sheets and TBII have worked well and been nice and strong. Forgive me for asking silly questions, this was my first time doing a skinning with PMF, so had no idea what to expect and was just surprised that it would come out so different than what everyone describes.

mikeschn wrote: by mikeschn » Mon Jun 27, 2016 6:51 pm
Hospital sheets are not very porous. I'd rip off the sheet and redo it with some cheap Home Depot canvas and TBII


Taking it all down it is, and TBII and Home Depot canvas is what I happen to have on hand. wish me luck that foam and window will still be there when I'm done. :frightened:

I'll post a pic of it when I'm done and hopefully it will be a :thumbsup: , thank u so much.

Re: PMF on foam door squishy

PostPosted: Mon Jun 27, 2016 8:07 pm
by ghcoe
I have had great success with Harbor Freight drop cloths. Usually you can pick up the 9x12 for around $16.00 on sale. They are usually on sale with a 20% coupon even better. It does have a seam down the middle. I have found that it is in the right place to get enough canvas to do two 4' walls though.

Re: PMF on foam door squishy

PostPosted: Tue Jun 28, 2016 7:10 am
by bonnie
Just a thought, but another type of glue might solve the issue. It would probably be expensive, though.


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Re: PMF on foam door squishy

PostPosted: Tue Jun 28, 2016 8:01 am
by GPW
Perhaps apply the sheets DRY ( Not wet or even damp ) over the glue , a very thin coat of undiluted glue should do it ... and you may have to still let it dry for a while ... :NC

Sounds like another TEST , a sample on a piece of scrap type of thing eh ??? :thinking:

Re: PMF on foam door squishy

PostPosted: Tue Jun 28, 2016 8:31 am
by KennethW
The sheets may not be cotton. The sheets may be a blend. It has come up before that a blend does not glue well.

Re: PMF on foam door squishy

PostPosted: Wed Jun 29, 2016 9:37 am
by lthomas987
KennethW wrote:The sheets may not be cotton. The sheets may be a blend. It has come up before that a blend does not glue well.


That would be easy enough to test with a flame. Take a bit of fabric and try and light it. The burn test is a tried and true fabric identification method. There's documentation on how to identify things based on how they burned. See below. A poly cotton sheet would almost certainly leave you with some hard melted plastic.

http://www.threadsmagazine.com/item/314 ... -burn-test
http://www.fabricmartfabrics.com/Burn-Test-Chart.html

Re: PMF on foam door squishy

PostPosted: Wed Jun 29, 2016 9:54 am
by GPW
Maybe they make those sheets waterproof for a reason ... :o :roll:

Re: PMF on foam door squishy

PostPosted: Fri Jul 01, 2016 11:05 am
by nagnificent
Thank You everyone,

OH my heart skipped a beat at expensive, Bonnie. :lol: I think they are right about the sheets though. And the TB should work great if I use the right cotton material. I will take your advice if in fact it doesn't for some reason though.

That is a great idea, the burn test. I never heard of that before, but that's a great way to find out. If they do test out as cotton, then I will have to do the test on a small piece of foam.

Perfect timing too, I just got my adds for Harbor Freight and there is a twenty percent coupon attached, so that is awesome.

You guys are great, and just as with my trailer and my second thoughts, this stopped me in my tracks and now I'm thinking it's for a reason. I was gonna install it just foam to foam using the hollow wall screws, but now it made me think it through again and I'm putting in wood at the attachment points and door handle. They say nothing happens by chance, this could be preventing me from having a door fly off on the highway. Made me stop gumbling and grouching about it too, :worship: :D

Re: PMF on foam door squishy

PostPosted: Fri Jul 01, 2016 10:40 pm
by KCStudly
I did a test comparison between 10 oz (IIRC) cotton canvas duck cloth PMF, and 6 oz FG and epoxy over blue foam. Once fully cured the both could be depressed with my thumb and not too much force; although they both sprung back fine w/o delamination.

It wasn't until I tested 2 plies of 6oz FG and epoxy that I was happy with the ability to resist point loading. I can still make the cured 2 plies move a little, but it takes a bunch more force and doesn't move much.

So if the glue isn't drying that's one thing, but if you just aren't happy with the strength of a single ply of thin cloth, then that is an altogether different thing.

The heavier canvas may give you what you want. :thumbsup: