Monday, May 24, 2010

Making Corner Molding in fiberglass.

Preparations are key to any good job and this is no exception.  I took this stage slowly, so will give details here to benefit.

To make the 2 'parts' (Left and Right), I made 2  molds/one for each side of the Cab-Over.. This is very time consuming and "Making a Mold" is usually ONLY done, if you want to make Not one, but Many/Many parts!  Much easier to just go out and build what you want right on the motor home if it's a "one shot deal".  Glass it up and be done with it!

..............  However, I live at a condo and have to bow down to their 'no work' rule.  SO, I'm building the molding 75' away in my garage, and then I'll take my motor home somewhere to install them!

The bottom line is, I'll take a 1,000%  more time to finish this job...  but for the rest of you, there will be info you might like to have and can use for other things.  Learning is good and if you have a better way that's
fine too.

The Mold, or Plug I made using scrap lumber.

You could actually use Foam, Cardboard, etc....you just need to get a 'replica'.   What "I" made,  was resined/glassed/sanded etc. to make a 'really fine/smooth' "EXACT Replica" of the object that was to receive the molding and that of course is the front end of our motor home. I did an earlier project here on Cab-Over Clearance Lights that did NOT require precision.  They came out wonderfully but precision was NOT necessary.  This molding, does need to be done right tho!........ and since it can be seen, it should be made with aesthetics in mind.  Well, at least that is how I feel.

You can use PVA as a Mold Release agent, or car wax or Pam Cooking spray, or even packing tape/cerayn wrap etc.---- and .....many other things.  Google this subject for more.
Heres the part still on the Mold and marked off for trimming.

I layed up 4 layers of Cloth 4" tape, using Surfboard Resins. I'M CAPITALIZING NOW !!  USE MORE LAYERS.
WHY? .......... I was correct that 4 was all you need, but 6 or 7 would have made the moldings so SO much more RIGID at this stage.....you know this is almost a 10' part!! Yikes!!.  My part is quite flexible, which is fine, but really tough to control in these final "Aesthetic" stages where I have to sand and fill to alleviate small imperfections.  If the PART was more RIGID, I could manhandle it more aggressively and get the next stage done quicker...thats all.  4 works, 6 or 7 layers would be my recommendation JUST TO MAKE THE JOB EASIER/NOTHING INTENDED  HERE ABOUT QUALITY!!

OK, to pop the Part off the Mold use thin little wood sticks/paint sticks etc. Shaved down on a grinder to give a Knife Blade end!  Slip this between the Mold and the Part and press or lightly Tap with a hammer.

As you see from the photos, the 'white-ish' portion is where the Part has left the Mold.  IF, IF, you have several coats of Mold Release, PVA or whatever, you can pop it off with you hands... no more tools necessary.

Next, mark your part for cutting with a Saber saw.  Try to hold it somehow.  I used a couple of pieces of wood in a vice for a 'jig'.  Would be just as good if you had a friend hold that dang thing while you operated the saw!

This goes quickly.  Cut OUTSIDE your lines and do the final with a belt sander or such.

I always Hand Sand using an 8-10" wood block wrapped in sandpaper/this gives a really nice straight line on the edges.

More later! :)

2 comments:

mike said...

I just wanted to Thank You for taking the time to post this. I have the exact same rig (only a 94) and have found (after a year) that the cabover has extensive rot. I priced repair and was quoted at 6K ! I only paid 8K for the whole rig! I found your blog and now feel confident that I can tackle this problem and do a whole reroof job to boot!! Thanks again and hope you are still enjoying your rig. I am, and I will will NOW for many, many more years thanks to you!

Ron Sheridan said...

Thanks Mike! We ARE still enjoying ours. Spent 4 months on the road this summer(16 weeks) and 16,000 miles. Florida to Alaska border, Islands of Canada's west coast, Hiadagui and Vancouver, then south through all western states to Death Valley and back to Florida.

Loved the trip and not one problem along the way that took more than minutes to fix.

Enjoy and again, thanks for your comments.

More travel come spring time!