Fiberglass Construction Techniques

[Steve Dunkel]

I've noticed that a few molded fiberglass RV manufacturers recess the areas around access doors, etc. instead of simply cutting out the fiberglass to receive a surface mounted fixture. How difficult is to form the recess from a manufacturing standpoint? Does it add a significant cost?

[Phil Underwood]

good question

[Andrew Gibbens]

How difficult is to form the recess from a manufacturing standpoint? Does it add a significant cost?

It appears to take no effort, because the mould provides the shape, but that's not quite true. There are two 'costs':
- the edges of the recess will require just a little more work when rollering-out (consolidating) the 'wet' fiberglass than a flat area;
- just occasionally a defect may occur on the edge of the recess, requiring a small repair before the trailer is finished, that wouldn't happen if there was no recess.

Actually coming up with numbers for those 'costs' would be very difficult, but I would guess they are at the 'some tens of cents' size. But in return, the recess defines where the fixture must go, which otherwise might require the use of a measuring tape, with the risk of an expensive mistake every 100 trailers (or whatever) of putting the fixture in the wrong place.

Andrew

[Reace]

The recessed areas are not difficult to add when building a mold and some fiberglass trailers do incorporate them. The down side is it doesn't leave a lot of options for customizing to the customers' needs.

I once considered recessing the tailights into the body similar to a motorhome with a fiberglass end cap. After looking over the catalogue for the light design I wanted, I phoned for a sample and found it had been discontinued. You could imagine having to redo a trailer mold because the tailights had to be changed.

When they quit making the Bargman L-400 latch, we had to make a new door mold to accept a newer style latch.

Things always change just when you don't want them to.


Reace

[Alf S.]

Hi: All... Isn't fitting the windows into a flattened area of the fiberglass better than fitting them into a curved area??? Don't the creases give the shell some extra rigidity???
Just my two questions worth!!!
Alf S. North shore of Lake Erie