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cboy 11-11-2009 02:57 PM

Can closed cell foam be butted together?
Is there a method for butting up two pieces of 1/4" closed cell foam without the seam telegraphing once the upholstery is glued on? Or won't it telegraph if the seam is perfect?

For the particular area I am working on (compound complex curve at the rear corner of the panel delivery) I do have the option of butting the 1/4" and then applying a layer of 1/8" over the top of that, which hopefully would do the trick. But if there is an easier way it would make my life a little easier.

454 Rattler 11-11-2009 04:37 PM

Hey Dewey, you think everyone is still at the parade ?

I'm sure you'll get some answers pretty soon.

Hey, keep up the good work.


302 Z28 11-11-2009 05:40 PM

I did it when I did not have a piece big enough to cover a door panel. It was 1/8" material, just make sure you get the meeting edges glued down firmly.


DanTwoLakes 11-11-2009 06:43 PM

What do Don Taylor and Ron Mangus say? It's foam, and foam can be glued together. Why not seam a layer of 1/8" foam and then put a full layer of 1/8" foam over it to get the 1/4" you want? The first layer will still need to be scuffed, so do a very good job of scuffing. How wide is the foam you're using? It's much easier to buy it 72" wide, then you don't have to worry about any seams.

cboy 11-11-2009 08:58 PM


Originally Posted by DanTwoLakes
It's much easier to buy it 72" wide, then you don't have to worry about any seams.

I'm not butting sections of foam because I'm short of foam. The problem is I'm covering a compound complex curve and to do it in one piece appears to me to be MUCH more difficult to pull off than to do it in sections.

DanTwoLakes 11-12-2009 07:02 AM

A picture of the area in question would help.

cboy 11-12-2009 09:01 AM


Originally Posted by DanTwoLakes
A picture of the area in question would help.

Not sure these will be of help for the question about butting foam...but here goes.

The first photo is of the general area of the rear compound/complex corner curve. Panel/section A is a separate piece that comes out separately from the upper portion of the curve (this was necessary to clear the seat belt mounting tab shown at the base of the curve). Sections B & C of the foam are the crux of the matter. They would be glued to the same backing board. I simply wanted to determine if the joint between these two foam pieces can be butted without it telegraphing and if so, any particular tricks for accomplishing that.

This second photo is a close up shot of foam sections B & C noted above and the arrow points to the potential butted seam between these two pieces.

DanTwoLakes 11-12-2009 09:47 AM

The answer is yes, closed cell foam can be glued together at butt joints. I would use foam to foam glue because the set-up time for the glue is only a few seconds instead of waiting for contact adhesive to dry. As far as telegraphing through the fabric, you need to sand the joints flat and then cover the entire area by using contact adhesive and gluing something else that is stretchable, very thin, and can be applied in one piece. While covering the entire area would be ideal, covering the butt joints by themselves with maybe an 8" wide piece may do the trick. This could be something like muslin or Versare. This should be enough to keep the joints from telegraphing through. Why not try doing a separate piece outside the car and see if this works for you. It's also possible that if you sand the joint well enough, the joint won't telegraph through without doing anything. Again, try it outside the car to see what works. I think you have a better chance of it not showing through because it is a concave surface rather than convex.

cboy 11-12-2009 10:26 AM


Originally Posted by DanTwoLakes
I would use foam to foam glue because the set-up time for the glue is only a few seconds instead of waiting for contact adhesive to dry.

I've been using K-grip to glue the foam to the panels. It says it is for foam to foam as well. HOWEVER, my fear with using K-grip is that it sets up Tooooooo fast. Using it so far I've found there is virtually zero ability to adjust the foam if you don't get it laid down exactly right the first shot. It bonds right now, like most contact cements.

And unlike the flat panels I've done, these small foam sections in the corner curve allow very little margin for error...I need to get that butt joint really tight and accurate AND I need to get the edges where the sections meet the flat panels on each side absolutely accurate as well. So I'm really concerned about how little leeway I have for adjusting the fit if I use a K-grip type contact glue.

I just got some 3M Super Trim to try out on some scrap piece to see if that might give me a little more breathing room to get those corner foam piece adjusted just right. You had indicated in the past that Super Trim would be adequate for vertical panels, just not overhead panels.


Originally Posted by DanTwoLakes
...sand the joints flat and then cover the entire area by using contact adhesive and gluing something else that is stretchable, very thin, and can be applied in one piece.

Would K-grip be appropriate as the contact adhesive for this part of the process?

302 Z28 11-12-2009 10:56 AM

I had a compound curve in the corner of my headliner where it rolls down to meet the side and back panel. I used one piece of foam, it was difficult but you can do it if you first place a couple of sheets of wax paper between the foam and the board you are wanting to glue it to. Start in the center of your compound curve and leave that area exposed from the wax paper. Stick it down and smooth it out then move the wax paper out a little on both sides and work the foam down. It may take you more than one attempt to get it right.


cboy 11-12-2009 11:42 AM

Here are some test runs as suggested by Dan.

The first pic is one of my early test panels done some days ago and shows what I want to avoid. On this panel I butted the foam at all four corners at a 45 degree angle. The arrow shows the shadow or telltale sign of this joint. When I put this panel together I knew the pieces of foam were not butted up tightly and I made no attempt to sand it or even it out. And this was the result. I think it is even more visible to the naked eye than to the camera.

Here are the tests I did today butting the foam pieces tightly using 3M Super Trim which did give me a bit less initial bite when the pieces are laid down and allowed me to form a pretty tight butt joint. I also then sanded the top surfaces paying special attention to the joint area. I did these tests with no muslin over the joint. The butt joint runs from top to bottom just about at the center of the vinyl in each shot.

I did two separate panels as pictured and the third shot is a close up of one of the panels. These were taken immediately after laying down the vinyl so I'll delay final judgement until the panels are completely set up and dry. But I can't detect any hint of the joint on either panel at this juncture.

Assuming I can create this tight of a joint between each section of foam on the actual panel, I should be in pretty good shape using your suggestions.

DanTwoLakes 11-12-2009 07:26 PM

Foam to foam glue is just that, it is not high temp contact adhesive, so no, you can't use it for all the steps, only gluing foam to foam in non stressed areas. It can be used for gluing the foam to the panels if it is a small area, or if there will be stitching or something else to hold it down, but not a large area because it will let go when the temperature is above about 110 degrees. I have posted tons of information on this subject, but you don't seem to have read any of it. You have read everything ever printed from anybody who has ever gotten a book published on car interiors, but you take everything I tell you as tainted in some way. I guarantee that I have BY FAR more upholstery credentials than any of the people whose books you have read. I CAN'T HELP YOU IF YOU WON'T LISTEN TO ME.
There are certain things you just can't learn out of a book, especially when you have a vehicle like yours that is unique, and nobody has ever tried to upholster one before. This is not a '66 Mustang or a '57 Chevy. You can't learn world class upholstery from a book without somebody standing right next to you while you're learning. You haven't even been able to get a simple curved corner on a small insert panel right (post 11), and that is a baby step. The panel you show in post #11 should have not been spliced anywhere, the outside perimeter should have been one piece and then there would have been no problem with a splice showing. Is there more waste by doing it that way? Of course there is, but it wouldn't have to be done over two or three times, would it? In fact, if you cut the foam carefully, you could have done the whole panel, including the center piece, with one piece of foam, which would have been far less wasteful. How much closed cell foam does it take to do it two or three times? You can be penny wise and pound foolish with a lot of things, but this is not one of them.

douglee25 11-12-2009 07:34 PM

Another option instead of using a straight butt joint is to scarf the joints at an angle. This makes for even less of a visible seam.


DanTwoLakes 11-12-2009 07:50 PM

You are correct that a scarf joint would be preferred over a butt joint, but no joints would have been the way to go. This could have been done without any joints. This is not steel or wood, it is foam that has elasticity and can mold to a shape.

douglee25 11-12-2009 07:55 PM

Agreed. If a joint can be avoided, definitely do so.


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