Altc Designs

[AriLea]

Sanding is coming along nicely. I have found a bit of a disturbing issue. Over time some parts of the underlying foam has expanded, just a little. This means the plug surface is a bit time/or/heat/or/moisture sensitive. I need to finish the tooling sooner than years, perhaps before next summer's heat. Around here that's as high as 120f. The garage is insulated so the max is lower than that, but no AC, so maybe 110f? And I need to not be surprised if I have to redo the mold parts at some point if expansion affects the initial mold set.

The molds I'm making break down into assembly sets. This allows me to update and reconfigure to make different quarter panel areas etc. For example, I should be able to swap out a section to suit a different headlight, grill, hood or wheel-well. By the same token I can replace a mold segment if the surface is compromised. Given this latest issue that might happen a few times unexpectedly.

 

[AriLea]

OK, done sanding on the body geometry on the left side. So, I went into the next step, adding surfaces that the molds will require on the left side.

 

[NSTG8R]

Sanding is coming along nicely. I have found a bit of a disturbing issue. Over time some parts of the underlying foam has expanded, just a little. This means the plug surface is a bit time/or/heat/or/moisture sensitive. I need to finish the tooling sooner than years, perhaps before next summer's heat. Around here that's as high as 120f. The garage is insulated so the max is lower than that, but no AC, so maybe 110f? And I need to not be surprised if I have to redo the mold parts at some point if expansion affects the initial mold set.

The molds I'm making break down into assembly sets. This allows me to update and reconfigure to make different quarter panel areas etc. For example, I should be able to swap out a section to suit a different headlight, grill, hood or wheel-well. By the same token I can replace a mold segment if the surface is compromised. Given this latest issue that might happen a few times unexpectedly.

Nice work! Unfortunate about the dimensional instability. What type of resin are you using? Epoxy's stable, but pretty pricey for something that size. I've read (because we only use epoxy here...no experience with it myself) that isophthlatic polyester resin is nearly stable. Probably moot at this point. You've gotta stick with what you've been using. But again, nice work!!

 

[AriLea]

Nice work! Unfortunate about the dimensional instability. What type of resin are you using? Epoxy's stable, but pretty pricey for something that size. I've read (because we only use epoxy here...no experience with it myself) that isophthlatic polyester resin is nearly stable. Probably moot at this point. You've gotta stick with what you've been using. But again, nice work!!

Because this is in my attached garage, I'm in a sub-division, and my wife's very sensitive to chemicals, I'm 100% epoxy. Worked OK up to now. For some uses I got epoxy from garage flooring kits at a discount source. But normally I get the stuff on Ebay at less than what Polyester would cost locally. Well, the whole structure isn't 100% epoxy, for example that grey coat is a latex paint primer. In a test it was stable with Epoxy. But I'll use lots & lots of mold parting wax, and that definitely is.

 

[Coss]

Do you have the problem with fumes drifting into the house?

 

[Frim]

Sanding is coming along nicely. I have found a bit of a disturbing issue. Over time some parts of the underlying foam has expanded, just a little. This means the plug surface is a bit time/or/heat/or/moisture sensitive. I need to finish the tooling sooner than years, perhaps before next summer's heat. Around here that's as high as 120f. The garage is insulated so the max is lower than that, but no AC, so maybe 110f? And I need to not be surprised if I have to redo the mold parts at some point if expansion affects the initial mold set.

The molds I'm making break down into assembly sets. This allows me to update and reconfigure to make different quarter panel areas etc. For example, I should be able to swap out a section to suit a different headlight, grill, hood or wheel-well. By the same token I can replace a mold segment if the surface is compromised. Given this latest issue that might happen a few times unexpectedly.

Stay away from Gorilla Glue for any purpose It never quits reacting with water or humidity.

 

[AriLea]

Do you have the problem with fumes drifting into the house?

With the polyester, yes anything toxic or smelly has been not so good. So I don't use even enamel paint in there. With the epoxy, no never a complaint. There is a little ventilation which seems enough for it.
But note, I do not use any solvents for the epoxy work. I toss things away such as brushes or cups, rather than clean, and I use gloves and don't let it touch my skin as much as possible I'm very patient.

 

[AriLea]

Stay away from Gorilla Glue for any purpose It never quits reacting with water or humidity.

Thanks! yes I've used that for a couple things, but it's nasty stuff. Expanding urethane foam insulation from the can is pretty much the same stuff.
One interesting test, I saturated 5 layers of plain corrugated cardboard with Poly-Urethane clear-coat. Then bonded them together with gorilla glue, crossing the corrugations. Man, that was almost as strong as plywood in load bearing. Was considering that for chassis construction at one point. I may still do that.
They use something almost as good as that for experimental garage aircraft.(in a fire the toxic fumes probably kill you in 5 seconds.. )

 

[Bill Anderson]

With the polyester, yes anything toxic or smelly has been not so good. So I don't use even enamel paint in there. With the epoxy, no never a complaint. There is a little ventilation which seems enough for it.
But note, I do not use any solvents for the epoxy work. I toss things away such as brushes or cups, rather than clean, and I use gloves and don't let it touch my skin as much as possible I'm very patient.

White vinegar can be used to clean up mixed epoxy. The mixed epoxy turns into a white emulsion that rinses off with water. You can clean gloves, mixing containers, spilled epoxy etc. I keep a vinegar soaked rag nearby my work to clean my gloves when needed, just dry them off with a clean rag and continue working.

 

[Coss]

With the polyester, yes anything toxic or smelly has been not so good. So I don't use even enamel paint in there. With the epoxy, no never a complaint. There is a little ventilation which seems enough for it.
But note, I do not use any solvents for the epoxy work. I toss things away such as brushes or cups, rather than clean, and I use gloves and don't let it touch my skin as much as possible I'm very patient.

When I was doing painting in my shop I ran into the same problem but came up with a cure. I made a temporary Paint Booth that will go up in about 5 minutes; ventilation is a large box fan blowing out at the bottom of the garage door. The booth is pretty much sealed at the top and has about a 10" gap around the bottom. Fumes will usually hang mid-air or go up; with the fan out the bottom it draws the fumes and blows them outside. I was surprised at how well it works. I sprayed a toolbox the other day in enamel and you couldn't smell any of it in the house (my garage is attached to the house, probably pretty much the same as yours). When I have a lot of machine sanding to do I use the same system and it keeps the dust way down in the shop and the house.