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chevynut
06-19-2014, 09:27 PM
I thought I'd try to keep moving on my interior so I started pouring the urethane foam today. This is a lot harder than I thought it would be, and a lot harder than it looks in videos of the process. You have to mix the two parts in a cup, stir for 30 seconds, then pour it. It starts to foam up almost immediately, so it's hard to cover a large area with it.

I need to pour about a 1" thick layer on the removable panel that's attached to my rear side panel. I built a "dam" around the removable section with cardboard (drywall shims) and tape, and screwed it to the side panel. Then I mixed the foam and poured it. The area is about 6" wide and 30" long, and the foam increases about 30 times in volume. It's hard to get it spread out on that large of an area so I ended up doing two pours back to back, and it came out way thicker than I needed it. I tried it on both rear panels with the same results. Looks like the gallon of chemicals I bought isn't going to be enough. :(

Here's some pics showing the dams installed, and then after attaching it to the side panel, pouring and allowing it to rise.


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Next I have to remove the dams and shave the foam down some. After that I will pour the next section of the panel which is not removable, by putting another piece of cardboard along the edge of the removable piece. There is also another small rectangular removable section down lower that will get a little foam but that should be easy. Once I get everything poured, I will sculpt the final shape of the entire panel. In front I have two removable sections and three stationary sections to pour.

Once I get the sculpted shapes I want, I will cover the foam with polyester resin, then with fiberglass and resin. I need to compensate for the thickness of the fiberglass, soft foam sheet, and leather by making the foam smaller than the final size. My interior guy also says he wants .110" between the sections when finished and ready for leather.

carls 56 (RIP 11/24/2021)
06-20-2014, 06:04 AM
they don't sell sheets that you could just cut to size?

chevynut
06-20-2014, 07:51 AM
Carl, yes they do sell sheets of polyisocyanurate foam and I have one 1" thick. I was going to glue pieces on and build up the layers to the thickness I needed. But the problem is these side panels are not flat...nowhere near flat. Notice in the pic on the right the bend that I would have to go over. I need to build up that area too, and a flat sheet would not work well at all. Also, gluing the sheets on would be a real PITA and I'm not sure it could even be done.

Pouring the foam eliminates all the problems with the curvature. It's not that expensive....about $50 for a gallon that makes 30 gallons of foam. It is kind of a messy process but it shapes well too.

Rick_L
06-20-2014, 11:14 AM
Sure looks like laminating some sheets would be quicker.

chevynut
06-20-2014, 11:48 AM
Sure looks like laminating some sheets would be quicker.

With what glue? What about the compound curves? I've looked at laminating sheets (even bought one) and I believe it's a lot harder than you think. You also have to peel the aluminum off the sheets to get the core out. Plus it could actually distort the panel itself if you could press and adhere a flat panel onto it. That's why pour foam is used so much by guys modifying cars. It's fairly easy to do, it's just not easy to pour a thin layer over a large area....that's what I meant about it being harder than it looks.

I even thought about spreading the foam as an adhesive and leveling layer and laying a sheet on it. I just think that would make a mess.

Rick_L
06-20-2014, 12:57 PM
Why would you want aluminum foil on your foam sheet? I was just suggesting using plain foam sheet, and if you need extra thickness, just glue as many sheets together as you need.

You would achieve compound curves with things think saws, files, grinders, and sandpaper. Maybe an electric knife. It should go really fast with the foam.

I would think that the same spray adhesive that upholsterers use would work. 3M #77 is one like that.

chevynut
06-20-2014, 01:17 PM
Rick, the only urethane sheet I can find locally is isocyanurate and it has aluminum on each side. I could order urethane online but it costs a lot and is expensive to ship due to the bulk. I only need the foam to make the shape so I can cover it with fiberglass.

If you use blue foam which is cheap and easily available, you have to use epoxy resin, which is about 3X the cost of polyester.

I think shaping a sheet of foam to match the panel is a lot harder than you believe. You can't have any air gaps with adhesives. I've looked into urethane adhesives to laminate them and it's not as easy as it seems, and a lot of people have had problems getting good adhesion. Apparently Gorilla Glue works well, but again there's the gaps to deal with. With the pour foam you don't have to mess with it at all since it conforms to the surface. It sticks to the aluminum panel just fine. I roughed it up with scotchbrite and cleaned it with acetone.

Pour foam makes stuff like this a lot easier, that's why people use it so often. I will use the saws, files grinders, and sandpaper to shape it. There are lots of ways to skin a cat, I just chose this way. If you saw the panels you might agree with the approach.

Rick_L
06-20-2014, 04:43 PM
Where would the gaps come from? If you had them, what about using pour foam or spray foam on gaps?

Why do you need fiberglass over the foam? I'm guessing you don't think the pour foam is strong enough to resist compression damage. If you had a denser, stronger foam could you do away with that too? It would seem that might warrant spending a lot more on sheet foam because you'd save a lot of labor. You might also be able to use some kind of filler on mistakes or to make the contour nicer.

Just thinking out loud here. I have little experience at this other than making some relatively high end stuff at work 40 years ago. On some nice molds with prepreg epoxy and honeycomb.

chevynut
06-27-2014, 01:49 PM
Rick, the gaps I spoke about would be between the foam sheets and the non-flat panels. You can't bend the rigid urethane foam very easily and I have some obvious bends in the aluminum panels. And no, I don't think ANY foam is strong enough to resist dents from knees, butts, etc. That's why I'm covering it with fiberglass. I have some chopped strand fiberglass and I plan to cover that with cloth for strength. To make sure the foam doesn't delaminate I plan to wrap it over the foam and around the edges of the panels. I can also use filler or put glass microspheres in the polyester as filler for smoothing. I plan to spray slicksand as a final layer to smooth everything out then spray epoxy.

The foam I'm using actually works out very nicely, once you get it shaved down to where you need it. Here's one of the rear panels roughed out to near net shape. I still have to figure the setback for the fiberglass, 1/8" foam, and leather. It's going to be about 1/4" on the top surfaces. The gaps between panels need to end up at .110".

Here's a couple of pics of one of the rear side panels partially completed. Notice the bends in the aluminum. The gap in front will be filled with another removable piece. That's the way my interior guy wants it. :)

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chevynut
06-27-2014, 01:54 PM
By the way, the armrest goes up to the rear of the side trim you see in the pic and the seat cushion covers some of the armrest.

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chevynut
07-10-2014, 12:33 PM
Yesterday I decided to try a different approach. I got a couple cans of "Great Stuff" spray foam insulation and sprayed it onto my panels. It takes a lot longer to expand than the pour foam I have, but the worst part about it is that it's more "rubbery" than the pour foam, even when fully cured. The can says you can cut and sand it but it sure doesn't sand as well as the pour foam.

I wish there was a way to add the pour foam through a straw or a sprayer like this insulation. My brother told me that taxidermists use pour foam and a black trash bag to control where it spreads. I guess they confine it to an area and they can actually move it around by hand somewhat. Problem is that if you work it too much it won't expand, and it also becomes "rubbery".

I'll keep trying. :)

Rick_L
07-10-2014, 07:36 PM
There are a lot of products out there. There's probably some that do what you want. Sorry, I don't have any recommendations.

That's one reason that I'd pursue something like I suggested earlier.

chevynut
09-03-2014, 11:52 AM
Made some more interior progress lately. I tried using canned spray foam but didn't like the bubbles and the more rubbery result. You can see it in the section by the door handle below. The pour foam is much easier to sand and much more rigid. I have everything poured and shaped except two sections on each front door panel. I only end up with maybe 10-15% of the foam left on the panels. The area of the armrest is about 3" thick, so I had to order more foam. There will be a removable armrest section that will be put on last, after the panels are anchored with screws to locate them more precisely.

I'm sculpting each section as I go, to get it to net shape. After that I will have to clearance everything for the fiberglass, 1/8" soft foam, and the leather. There's a lot of work in these panels and it's easy to see how a custom interior ends up $20-30K!

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Here's what it's going to (or supposed to) look like when finished. I want to put a chrome strip between the charcoal carpet at the bottom and the tan leather, so that will be interesting since it's about 2" thick foam there:

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Colors are charcoal and tan/beige. I have a preliminary design for the cargo area too. I'm not sure what will be in the center where I show a fender bird, nor do I know what color the console extension will be. The cover will be removable and everything underneath will be charcoal leather and carpet. The carpet will be wool from a Mercedes as will the charcoal headliner material.

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chevynut
09-04-2014, 09:51 AM
Here's a better pic of my cargo area showing the charcoal and tan leather. The pointed "oblong" areas are 6x9 speaker grilles, probably made of polished stainless mesh or perforated sheet. The floor below the cover will be charcoal carpet as will the inside of the tailgate and the back of the "package tray". The tubs will probably be charcoal leather. I'll most likely use stainless trim on the sides of the floor, similar to the stock trim.

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chevynut
09-04-2014, 09:59 AM
FedEX just came with another gallon of urethane pour foam. Just in time!! :)

chevynut
09-05-2014, 02:12 PM
Got the dams ready to make the big pour in the center of the door panels. This foam needs to be 3" thick at the armrest, tapering to the back. I have found that it's difficult to pour such that you get a taper. Usually you end up with a lot more foam than you need in some places.

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chevynut
09-05-2014, 10:09 PM
Well this was interesting. I used about half of my gallon of foam on these two pours and had some areas too thick and some too thin. I had to add some foam near the rear of each panel and may have to add a little more. I did better on the passenger's side as far as controlling the thickness front to rear.

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After the foam cured I took a saw and roughed out the shape so I could start sanding and filing. It's best to take as much off as you can in pieces, because the sanding makes a huge mess and it gets everywhere. This is after sawing chunks off....it's like cutting dry bread.

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Next comes filing and sanding the final shapes. I need to do one last pour at the bottom section, but that should be easy. I need to mount the courtesy lights first.

I got some glass microspheres to mix with the polyester resin to use as filler when I'm doing the fiberglassing.

chevynut
09-09-2014, 06:03 PM
Got the last section poured and both front panels roughed out. I cut out the holes for the courtesy lights and I still need to figure out how to attach them to the panel. I was kind of afraid they might warp when I put the foam on but I put all 4 of them in the car to check for fit, and they fit really well. The clips and screws hold them in place nicely. Now I need to re-fit the rear armrest to the panels. I still need to fab a pair of removable front armrests out of aluminum and figure out how to attach them.

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567chevys
09-09-2014, 06:45 PM
Looks really good , When you get them done send them my way I will try them on my car !

Are you going to make them and sell them when your done ?

Sid

carls 56 (RIP 11/24/2021)
09-10-2014, 05:02 AM
good job, that is coming out nice. :cool:

chevynut
09-22-2014, 09:09 PM
I got the top section near the beltline clearanced today, and plan to start laying up the fiberglass in the next day or so. I think I'm going to put two layers of 4 oz. glass cloth and 2 layers of 1.5 oz glass mat on it. It's weird, but the glass cloth is weighed per square yard and the mat per square foot, so the mat is actually thicker. This layup should get me somewhere close to 1/16" of overall thickness, which I think is plenty. I'll do the final clearancing of the sections as I go, to make sure the leather fits tight.

chevynut
09-26-2014, 11:34 AM
Well I cut the foam down to 1/4" from the height I need it (1/16" fiberglass, 1/8" upholstery foam, and 1/16" leather). I found out I can only use one layer of 4 oz. cloth and one layer of 1.5 oz mat to get the thickness I need. I'm surprised that the resin adds that much but the mat seems to absorb a lot of it and it swells. It starts out about .020" thick and probably swells to double that. I used a lot of resin so I had something to sand away, and it turned out almost spot on. I only have the top sections of the front panels done so far but the spears fit really well. Getting the gaps right is time-consuming.

scmense
12-21-2014, 08:33 PM
Update

chevynut
12-22-2014, 07:45 AM
Continued here:

http://www.trifivechevys.com/showthread.php/3495-Progress-on-door-panels-and-rear-side-panels