Hi everyone, Hoping for a bit of help here. I'm in the process of tearing down a 1969 Franklin Mini. As the job progresses I am of course pondering the job of putting it back together.
One area where Franklin seems to have excelled is in the sealing of the corner where the roof/rear sheet meets the wall sheet. They used what appears to be similar to fibreglass sheet in appearance with a soft putty or similar in/on it.
After 40+ years, whatever the tape is saturated in is still soft. I've had a small piece on my workbench for a week now exposed to the air and it too is still soft and pliable. Has anyone seen anything like this and knows how I can duplicate it?
Also, has anyone ever removed the interior wall sheets on a Mini? Is there a frame or is it a composite construction with frame only around the perimeter?
Hope somebody can help with either question. Cheers Jim
Thanks geoff 'n jude From what I an determine from reading those sites, it appears the product is "set" by applying heat. I'm getting the impression it then becomes hard and probably quite strong since its designed for the aviation industry. I don't think its what I'm looking for. Thank you anyway. Cheers Jim
Wow, what a project! I love the concept. Thanks for linking to it. I would never have found it in the "Whatever" section.
I have flashing tape in the back of my mind already. Unfortunately its not exactly what I'm looking for. Firstly, its quite thick compared to what Franklin used plus, I've had call to remove some old stuff from houses over the years and it does eventually go quite hard and brittle. Perfectly ok in the appliation it was designed for but on a van bouncing down the highway at 100kmh?? maybe not ideal.
Thanks anyway. I'll keep looking. If I can't find anything better, flashing might be the go. It does have the advantage of having a 100% impervious layer in the aluminium top cover.
Hopefully I can give some snippets of information that might be useful for your van.
Franklin built a brand new factory at Wendouree, next to Ballarat, in 1967. This "state of the art factory" included new production methods, one of which was the construction of the walls for the caravans. The new method was to build them laying down on a large bench, and then lift them to the side of the van as a complete wall. The wall was made as a "sandwich", with the cladding, frame, and internal ply all glued together with 3M glue.
I can't recall anybody on the forum actually dismantling a Franklin from the new factory, but I suspect you will have a bit of a challenge trying to pry the internal ply off. I guess a lot will depend on how well the 3M glue has stood up to time. Quite often we see the glue bond in the actual layers of normal plywood lose its adhesion over the years since the vintage days, so it's quite possible the 3M glue also suffers from an ageing process, and ends up being easy to separate.
If you end up having a go at it, keep in mind that you'll become the resident expert on the forum for other Franklin owners, because I think you'll be the first to do it.
It's interesting to hear you talk about the tape used on the corner joints. I have a bondwood van in the shed which is allegedly a 1956 Franklin van. I bought it 7 years ago, and it is still sitting on a "To Do" list, waiting for the restoration fairies to come and give it a cuddle. About 5 years ago, I attempted a start on that project and took some of the roof cladding and side cover strips off (it's not the same van as I'm working on now - One can't have too many of these projects, can one? ).
The roof was originally bondwood with a duck canvas cover. A number of years after it was built, the roof was covered with galvanised sheeting. I took that galv sheeting off when I was mucking around with the van. Each sheet was soldered at the lap joint, but funnily enough just inside the lap joint there was a strip of the same sort of tape that you speak of...
This is the van, and you can see the mid-level horizontal joint in the ply, and the darker strip of the same tape. The tape was also under all the J-moulds on the edges (right hand photo), but unfortunately had not permanently protected the four bottom corners of the van, which ended up getting severe woodrot (something you should check closely on yours)...
This is a close-up of me peeling the tape away from the side wall joint. Just as you have found, the tape on my van was quite flexible and looked like a cotton woven tape that was saturated in some sort of sticky substance. After peeling the tape away, the remaining sticky residue could be cleaned off with turps...
At the time I was mucking around with this van, I started to do some research about that tape, trying to find out what was available these days that would be a good substitute. I discovered on one of the internet caravan parts suppliers websites that they listed a Denso tape that was apparently used for sealing caravans in the old days...
When I made some enquiries, they no longer stocked it, as it was no longer used in the caravan industry. I searched for the Denso website, and they make various sealing tapes for the mining and heavy industry applications. But unfortunately for you, that's where my story ends. I never went any further with the research because the project got shelved. But I'm sure somewhere out there, there is a tape that would be a great substitute for the tape you've got on the van.
Hello Jim & Al, Denso tape you say Al, this was the first thing that I thought of when I first saw Jim's pic, when I worked with my dad this was a tape that we sometimes used to coat pipes (anti corrosive) it is as you say some type of cloth that is impregnated with a substance (not sure what it is ) but from memory it seemed to me to be more greasy than having any sort of adhesive properties, dad cleaned out his shed a while back and gave everything to me so I would need to have a look, but I may just have some here left over from the old days, will get out in the shed one day and get back to you if I can find it.
If you get an email telling you that you can catch Swine Flu from tins of ham then delete it, it's Spam.
Hi Grandad, Franklin1. I'm a sparky and have used denso tape for many years around the bottom of galvanised power poles to stop corrosion It is still used today in the electrical trade for the very reason you need... Waterproofing! We wrapped it around the bottom of the pole all the way up to about 6" above ground level and when the pole was concreted in it provided a moisture barrier between pole and concrete. Great stuff! Made to last ;D As you described it doesn't go rock hard and that's why it would be great as a watertight joint sealant on bondwood ( or anything else for that matter!) think you can paint over fit ok depending on what paint you use ?? Would have to experiment maybe with that See link: compare.ebay.com.au/like/230884331119?ltyp=AllFixedPriceItemTypes# Hope this helps Cheers Andrew
... it is as you say some type of cloth that is impregnated with a substance (not sure what it is ) but from memory it seemed to me to be more greasy than having any sort of adhesive properties....
I have worked in the instrumentation field before and used to use Denso tape to wrap around pipes, instrumentation sensors, especially temperature sensors and wiring to protect it against the harsh outdoor elements. It sure is a new level of stickiness that you can not explain unless you have touched the stuff yourself. However I was always told that the greasy material came from pig fat.
A big thank you to everyone who have responded to my questions.
I've asked for advice on two items and so far this forum is batting two for two. Not a bad track record.
I've bookmarked the Denso tape for purchase when I get paid next. I suspect there are probably more modern and most likely better products in use now. It has been stated caravan builders no longer use this tape. However, despite not restricting myself to a faithful restore I'm still going to use Denso because I've seen with my own eyes how well it performs. I will however use a modern adhesive under the roof cladding to the wall edge.
Al (Franklin1) Thank you for the history. Its nice to have confirmed the walls are of a composite construction. The adhesive that Franklin used has stood the test of time. Its still doing the job. Having said that however, it appears to be a relatively easy task to break the bond. Whether I could have done so when the van was new is debatable.
I've been pondering the reconstruction of these walls for quite a while now. What I have in mind is a bit fiddly and roundabout but I think its the safest way at this stage.
Briefly, I'll lay the wall down and remove the inner ply, and then reapply new ply using any one of a dozen or more modern adhesives. I've done a little bit of research into the adhesive and there doesn't seem to be any shortage of choices. Its just a matter of digging deeper to narrow the choice done.
Each wall will require 3 sheets of 8x4 ply. I can glue them on as full sheets then use my router to trim to exact size. The aluminium extrusion around the edge will make the perfect template.
Then, I'm thinking of removing the outer cladding. Once this is off, I should be able to use a Stanley knife to trim away areas of the polystyrene so I can add some internal framing to provide support for the front couch and rear bed, and probably the overhead cupboards as well. Glueing this to the internal ply with some liquid nails should give me a strong bond.
With the walls in this condition, I should be able to rebuild the van and I can now get to the back of the ply to attach cross spars/roof rafters. This is a feature not present in the standard construction. I need the rafters in order to be able to insulate the roof and attach the ceiling panels.
Then comes the tricky bit. I have to refit the cladding but this time the fit must be precise to meet the edges at exactly the right point. There will be zero tolerance for the fit. I feel that so long as I choose a glue with a fairly lengthy open time, I should be able to nudge the cladding into the exact position before I apply any clamps. If I leave the roof cladding off while doing this, I should have open access all around the wall to use as many clamps as I need for the job. Obviously I'll have clamping boards to get pressure into the middle of the wall.
I must remember to put some marks on the cladding and edge of the wall to use to realign. Whats the bet I forget to do this until its too late?
Clear as Mud?
Anyway, thanks again to everyone. I'll link to this thread from my build thread so others in the future can find it ok.
Hi Jim. I have a roll of that damn tape somewhere & recall posting a pic of it couple or so years back. It is still as moist & gooey as was back in the 60s. We used it when rivetting all panels to the frames on the buses we used to build.Problem with it then was it leeched moisture along the joins & we used kero to wipe clean. These days they run a bead of sikaflex type sealant along the frame & push the panel hard up to it & clamp until secure.No rivets.I helped fit an 11m panel to a coach my old boss was renoing a five years ago.Hasn`t fallen yet.But that`s how bus panels are done now.Love your reno story.Great read. gordon
Queenstown Tasmania. 1948/52 Mercury Teardrop. 1959 Phase III Vanguard Vignale.
Gordon, do you happen to remember which Sikaflex it was you used? There are so many to choose from and some sound very similar in what they do. I had already 99% decided it would be one of their products but exactly which one is a debatable point.
Also, can you elaborate on what you mean by "Leeched moisture"? Jim
Hi Jim. No idea as its what used in the industry today.You just wouldn`t use it on a `van as you`d be hard pressed to remove it once its set. The old denso tape would ooze brown moisture particularly on a warm/hot day if it hadn`t been trimmed 1/8" inward (leading edge) from one sheet overlapping other.This of course had to be done prior to painting.Sometimes even after the bus was finished we`d find a little seepage/leeching.Wiped totally clean & dry & painter would have to brush a paint line down the seam.Usually worked. Sikaflex is whats used on vehicle windscreens.Can be irksome as you`re probaly aware if having to replace screen.I really can`t see why a good silastic can`t be of use to you though. gordon
Queenstown Tasmania. 1948/52 Mercury Teardrop. 1959 Phase III Vanguard Vignale.
I've just come across your thread about the sealing tape used on old Franklins. Did you end up sourcing and using this Denso tape to reseal your van. I've had a look at the Denso website and you can get 2 types; 1 - Denso tape serviceable to 55 deg C and 2 - Densyl tape serviceable to 75 deg C. I am about to reseal my 69' Franklin and have been tossing up as to what sealant to use?
Hi Alex, Only just noticed your PM drawing my attention to your question here. Sorry for the delay. I haven't reached the point where I'm doing that job yet but I have decided on how I will do it.
I've decided to follow the advice of a member of the Caravanners Forum which deals with modern vans.
This fellow is often quoted as a knowledgeable source of info on repairs etc and is a professional caravan repairer in Qld. I figured there have been a few advances in sealants in the past 45 years so I'm going with Sikaflex.
Details can be found HERE on which Sika product and how to use. Look for posts from "cabcar"
Thanks for the reply, I read the link to the other forum. Sounds like most people go with sikaflex. I got hold of some of that denso tape anyway so I'll have a quick look at it. Can't be all that bad after 40 years the original tape has only failed in a couple of spots where it had hardened. The main places my van has leaked is in all 4 corner Perspex windows. I will be doing those with butyl mastic. Ended up getting those windows re-fabricated, much better than the old crazed ones.. I'm just at the point of putting all the trim back on so I'll let you know how I go.