Making fiberglassshower pan

[Zeppelinium]

This is an experiment. No guarantees on where this is going.

The objective is to make a one-time mold which will be coated with gel-coat, then fiberglass and resin, to achieve a strong and smooth part.

First step is creating the mold. For the shower pan, the mold is sized 1/8" smaller all around than the desired outside dimensions of the shower pan. The whole mold could be created from rigid foam, but it's easier to find standard buriable exterior insulation and use that as an easily shaped surface on a plywood box.





The next step is to do a fit check, then bondo the entire mold and sand it smooth. More progress expected after the Restoration Rally this weekend.

Zep

[HiHoAgRV]

I used the same method years ago and got fair results. The weak points in my effort came from using Bondo to smooth the mold. Even with a coat of epoxt paint and lots of lube, things stuck a bit but I was able to get two or three parts off before the mold was useless.

A pal has made a bunch of custom parts for hotrods with good success.

My gellcoat was a useless try. I ended up sanding, filling and painting the final parts. They were however bullet proof!

Keep us posted.

[Zeppelinium]

Originally Posted by HiHoAgRV

...The weak points in my effort came from using Bondo to smooth the mold. ...

I have heard that you can use epoxy resin to fill and smooth the mold, but that seems like an expensive path. And you'd still have to have a successful release agent.

Zep

[VIKING]

I have read about this process in a model airplane mag. An author was making molds for fuselages and wings and such and his process was to finish the mold out with epoxy resin. He used the finest cloth he could get away with so it would not be too difficult to fill in the weave. I recall him saying that the mold was the part that needed the most attention to detail, so it would be strong and very smooth & uniform over the entire surface.
If I can find the article I'll share it here.

Best to you Zep,

Rich the Viking

[68 TWind]

Check out West System Epoxy if you need resin. I have used lots of it restoring my Trade Wind. Aircraft Spruce or West Marine (not the same company) has it. It is used my boat builders and experimental aircraft builders. They have a complete system for all filling and glassing needs.

Also, they have a lot of videos on Youtube on how to select the right product and how to use it.

[vinstream]

Zep... I must point out one tinny flaw! You must tapper the sides with some type of angle or it will not pop out of the mold! Your flat sides will bind when you go to remove when finished. You will always see a curve or angle in fiberglass molds for this reason! Also I would add two to three air fittings! Glass them right into place! place them so that they will leave a bump in finish product that you can sand down to correct level. Simply attach high pressure air hoses to the mold and when ready the new tub will pop right out!

Hope this helps! Good luck....Todd

[Zeppelinium]

Wow, glad I went back in the shop last night and tapered the mold, but only by 1/8" on three sides (the other side is designed to slope 3/4"). I'm thinking that taper might have to be increased, but it only took about 2 minutes on the band saw.

The orginal part tapers about 1/2" on each side.

On the other hand, this is a one-time use mold, so destruction to remove the part isn't an issue.

Zep

[NorCal Bambi]

Zep, thanks for this thread. I'll be doing some mold work on my 55 Cloud when I get to the interior. Your experience will be helpful.
Don

[JLGT5107]

Looks good Zepp. I'm taking a stab at this myself on some new taillight housings. To create the mold I returned the old ones to thier original appearance with sheet rock fiberglass tape,epoxy and bondo. Primed sanded and applied 10 coats of Maguires car wax. On the first one I brushed on two coats of gelcoat, but sprayed the second one and got better results. On the finished product I will probably spray 3or 4 light coats of the gelcoat. I made a plywood form at the beginning to hold the parts as i was working on them. It made it much easier. I then brushed on a full coat of epoxy , and started builing up the matt which I had torn up ahead of time. Its hard to judge the thickness of the build as your doing it, I guess it just comes down to experience. The molds are now ready for making the part but I'm working on the frame and floor until I get a rainy day to make the parts. I bought materials online at "Fiberglast" good price and fast delivery

[Zeppelinium]

OK, let me see if I decifer you photos correctly.

In the upper left photo, the left part is the old one and the right part is the new one.

In the upper right photo, you're refurbishing the old part with tape and bondo so you can make a female mold on top of it (covering the outside, visible side of the old bezel).

In the lower left photo, that looks like a male mold made from the inside of the old bezel. I don't get how that allows you to make a new part with a smooth outside surface.

The lower right photo appears to be a female mold viewed from the non-working side. Is this made from the green male mold?

Help a dummy out here.

Zep

[VIKING]

Hi Zep,
It appears to me that the first pic is one old repaired bezel and one old un-repaired bezel.
Upper right looks like the beginning of the old bezel repair.
The lower left looks like the new mold after removing it from the original bezel.
The lower right looks like the original bezel in the plywood holder.
Or maybe not....
He says he hasn't made any of the new bezels yet.

Just another shot in the dark!

Rich the Viking

[3 Dog Nite]

I'll be following this one closely. I'm imagining my custom made end caps.

Ricky

[JLGT5107]

Top left: Old left side bezel as removed from trailer. Cracks,missing pieces and uv
damaged. The previous owner had broken out the back to install a deeper tail light.To the right is the right side bezel {they are not interchangable] after
all repair and primer.
Top right: back side of bezel with fiberglass tape and epoxy prior to bondo work, which will bedone from face.
Lower left: Fiberglass laid over old bezel after wax and gelcoat. Mold is sitting on
my plywood buck which is not a requirement but makes the messy buisiness more controllable,
Lower right New "mold" has been removed from old bezel "plug".Sitting in second plywood buck There are some minor sanding scratches and pin holes as well as some lines from a couple unrepaired cracks that I am smoothing out so they wont
be in final "part"
Next step will be to fair out bondo. Prime. The priming is where you will see all the minor imperfections that will really annoy you in a glossy finished product. then Wax and Gelcoat. If I can figure out how to tint gelcoat i will not have to paint later. Lay up fiberglasss, trim, paint and install. All of this info can be found on youtube.

[JLGT5107]

I just removed the rear end cap in mine. It just needs to be painted and maybe a few minor scratch repairs. When you remove it you get a sense of how big it is. Its really big, I don't even know where I'm going to store it. It is extremely flexible and will be difficult to get out of the trailer without cracking. It could be easily used as a plug for a new mold, but would require a lot or set up time and space for staging and bracing. The material costs will be substantial. When I get to the front of the trailer I may cut out existing cabinet opening and match rear profile. This will give me more flexibility in building storage there. Also I will be working in wood which I have a better feel for.

[Zeppelinium]

Originally Posted by JLGT5107

...Lower left: Fiberglass laid over old bezel after wax and gelcoat. Mold is sitting on my plywood buck which is not a requirement but makes the messy buisiness more controllable, ....

I assumed that the mold over the old part wouldn't have that kind of detail on the "outside." Got it.

Originally Posted by JLGT5107

...Lower right New "mold" has been removed from old bezel "plug".Sitting in second plywood buck There are some minor sanding scratches and pin holes as well as some lines from a couple unrepaired cracks that I am smoothing out so they wont
be in final "part"....

I couldn't ever have figured this out. My eyes were telling me that I was looking at something that was proud, not recessed. As soon as I started looking for it to be the mold, POP, it flipped to the correct configuration!

Thanks.

Zep

[VIKING]

Originally Posted by JLGT5107

I just removed the rear end cap in mine. It just needs to be painted and maybe a few minor scratch repairs. When you remove it you get a sense of how big it is. Its really big, I don't even know where I'm going to store it. It is extremely flexible and will be difficult to get out of the trailer without cracking. It could be easily used as a plug for a new mold, but would require a lot or set up time and space for staging and bracing. The material costs will be substantial. When I get to the front of the trailer I may cut out existing cabinet opening and match rear profile. This will give me more flexibility in building storage there. Also I will be working in wood which I have a better feel for.

Your end caps are probably fiberglass, and if so, very durable and flexible. If they are VERY thin and cracking, they are abs plastic garbage.
I'm thinking of making a wood or aluminum front end cap for my Safari. I don't like the formed front end cap either.
If you have abs you can fiberglass the back of it to strengthen it, and then bondo any holes and cracks prior to painting it.

Best to you,
Rich the Viking

P S. I was able to walk out the door of my Safari carrying each end cap by myself. It was a lot easier than I thought it would be....

[JLGT5107]

Zepp, I dont want to hijack your thread, just thought relevent.
From what Ive researched, the mold suface should be pretty rigid and smooth. I know some people use the foam but dont know how they
handle the porosity other than bondo or equivelent. The other question would be , will the resin attack the foam? Primer on the mold will be sufficient , I used gelcoat just to get the feel for it prior to the finished product. The fiberglass suppliers have an inexpensive "parting solution" to spray on the mold , which greatly eases removable. Im trying to work out a mold similar to yours for black tank, but am concerned about having a seam.

[Zeppelinium]

You're right about the foam. It needs a hard, smooth surface. You can get that with bondo and epoxy paint. You can even paint some resin with filler (wood dust or micro balloons) on it, then sand lightly.

Zep

[3 Dog Nite]

JLGT5107, don't worry about a seam. Once the 2 parts are married together, They can be sealed with the same material you make the tank out of. Just be sure to reinforce it with the tiger hair or whatever you
ll be using to make the tank.

Ricky

[blickcd]

Zep,

Looks like your project is off to a good start. I assume you are replacing a cracked shower pan that is no longer available or is extremely expensive.

I was wondering if it was possible to take the broken pan and lay up some new fiberglass on the inside, then gel coating it for a clean and restored look? I only know a little about fiberglass work but assuming you could get a good bond between the new and existing resins, the restored and reinforced pan would be pretty strong.

Christopher