Sealing the 1966 Avion

Background

When looking over the Avion I found that in many places there was remnants of old brittle sealant. I am not quite sure if the long seems at the endcaps and panels were sealed from the outside at the factory but since there were some small leaks I decided to do them all. The caulking around the windows for sure needed an update. I also found that the roof was covered with something that looked liked a mix of tar and horse hair and the material had several small cracks.

Materials:

Sealant: There is 2 recommended, Vulkem 116 (Amazon) or TremPro 635 (Vintage Trailer Supplies) both in grey. Regular silicone or bathroom sealants are not for RVs. TremPro feels much like a regular sealant while Vulkem has a more grainy texture and dries a bit harder. Vulkem can be removed with isopropanol or ethanol while soft, it is moisture curing and has a long list of hazard warnings. I like Vulkem a bit better, although TremPro claims it's the modern replacement for Vulkem.

Roof coating: There is a huge choice of different roof coatings. There is 2 basic types, silicone based or acrylic based. I prefer Acrylic, Silicone ages faster and nothing adheres to it except for more silicone but it is thicker and needs less layers. I wouldn't use stuff from the hardware store made for a house, RV sealant is more flexible and adheres to many surfaces. I used this one: Ames MMS1 (Amazon).

Patch Panels: To patch holes I used either round aluminum cut-outs or anodized sheets. I got these from amazon but found that Home Depot also sells large and 12X12 aluminum sheet. For some patches I used un-anodized aluminum, a good idea could be to paint these with aluminum paint to match the anodizing.

0.039" thickness works best but 0.02 inches is OK.

- Feelers 4" Diameter Aluminum disc 1060 Aluminum Round Sheet Plate Stamping Blanks 18 Gauge (.039")

- Feelers 2" Diameter Aluminum disc 1060 Aluminum Round Sheet Plate Stamping Blanks 24 Gauge (.02")

- Metal Engraving Sheets for Etching, Blank Anodized Aluminum

Tools and supplies: A painters knife to remove old caulking, a caulk gun, 2-3 rolls of masking tape, nitrile gloves, alcohol, paper towels.

Avion Travelcade Sticker: Ebay

Preparation:

I washed the trailer with simple green but everything that does not contain wax should work. Next I treated with Star Brite (see "Making it shine") and washed again. I then made sure that all the seems were dry. I found that there were leaks at the radio and TV antennas, I removed the antennas and patched the holes with a 2" discs.

The best time to remove old caulking is after taping (see below) this prevents scratching the surface.

Sealing the roof:

I am a proponent of doing what's necessary but stop there. The old roof coating had some cracks but still was attached fairly well. I saw no reason to remove it completely- which is a long and painful task. I applied 3 coats of the Ames MMS1 and it holds up very well and filled all the cracks. To make it look pretty I used masking tape for a sharp edge.

Do not walk on the roof- or only with a sheet of plywood to distribute the weight. The weight on the panels can stretch the holes at the rivets and create leaks.

Etarnabond tape: I am not a fan- this might be a short-term fix for a leak but there is a good chance water will creep under sooner or later. The tape builds a barrier for water to sit and especially at overlaps capillary cracks can form. The older Avions with 13-panel endcaps have a roof design that does not need any tape. Caulking works much better than tape.

Sealing the seams

I sealed each and every seam with Vulkem. I am not very good with running thin lines of sealant and found the best method is to mask both sides with masking tape, apply the sealant and press it in and flatten it by running a finger along the seam. This allows to keep the caulk in a narrow line. I removed the tape right after sealing, carefully not to touch the camper with the soiled tape. Vulkem can be easily removed with alcohol while fresh.