Walt
Thanks for giving us the outcome of your trial - like you I have found that CA makes a poor bond with PET.
I’m hoping soon to hear the outcome of the Acrylic tests from our West Country laboratories
andrew
Andrew - nothing but a miserable failure - sorry
will try again this weekend but abrade te surface
Rgds
AndyT
Every day - if we are not careful, we learn a new thing:D
Sticks like sh*t turns out to be a MS polymer!
There - isn’t that interesting!
MS is modified Silane, and the RTV silicones are technically polysiloxanes
I found it while hunting health and safety data sheets:
http://www.cromwell.co.uk/static/publication/485/pages/1348.pdf
I can’t immediately remember if any of us have tried silicones, but I will give it a go tonight. I have a Fiat industrial gasket silicone - RTV - one part
We have a trial of Stabilit Express under way, I believe, in Keynsham (Spelled K-E-Y-N etc), and AndyT is indefatigably trying solvent cleaning and roughing up the PET surface before re-trying his Acrylic adhesive.
watch this space
andrew
Might want to look here as well for a bit more info…
Fellow Skippers
My daughter is a product development and research chemist that works for a plastics company supplying resins and she responded with the following:
“On the PET question, that is a tough one. I think the key is that it does
need to be an adhesive and I don’t have much experience in this area.
There is a local company (Akron, Ohio area) formerly called “Mac Tac” now a part of Bemis company who works in the adhesives area. You would need to find anadhesive which has a strong affinity for the PET for sure. The only otherway is if the materials can somehow be spot melted/welded by heat. This creates chain entanglement of the polymers. For PET this would be
difficult because the melting temperature of this type of polymer is quite
high compared to polyolefins like polypropylene or polyethylene.”
About 35 years ago, I needed to vacuum form some custom covers that were about 6" x 8" x 2 1/2" deep and just went to a local plastic company and bought a sheet sliced into pieces that would fit our former at the university where I taught. It was Acrylonitrile Butadiene Styrene (ABS) and can be welded with MEK and there is good adhesion with mechanical bonding. I believe boats such as the Fairwind, Soling and V-12 use ABS.
I know you like the idea of using “free” soda bottles, but here in Michigan they are not free. We get 10 cents to return them.
Frank
By the way, for those living in the US, I use this company for my plastics. The website shows the type of standard plastics they sell. They are in Flint, Michigan which is not that far from Milford, Mi where race week with be held this Fall. Schedule below.
http://www.sorocproducts.com/plastic.htm
For about $15, they cut out 5 pieces of 3/8" plexiglass to my dimensions so I could make my Footy measurement box.
MI Sep 27-29 National Championship Milford Soling 1 Meter
MI Sep 30-2 National Championship Milford US 1 Meter
MI Oct 2-5 National Championship Milford East Coast 12M
MI Oct 30-2 National Championship Camp Dearborn IOM
Thanks for the contributions - there WILL be a great adhesive for PET and it would be good to identify it.
I have some results of a test - they are unclear at the moment but promising, I hope.
1-part silicone RTV
I made two test specimens to try silicone rubber as an adhesive (one part, acid cure, black RTV silicone). One was a shrunk hull part, and the other a slice cut from the same bottle.
The hull I wiped with acetone as a degreaser and bonded with the silicone clamping all the way round
The strip I degeased with acetone and abraded one part with aluminium oxide “sandpaper”. Then bonded and clamped
Left for 24 hours to cure
Result - the hull joint peeled apart with ease - a definite FAIL
The strip cannot be pulled apart, nohow!
So promising, but not conclusive. I will try some more test specimens with abrasion and degreasing combinations and see what makes the difference - it could be something like a mould release on the outside of the bottle only.
I’m also busy preparing my boats for the UK Nats this weekend, and plan to get VoooorTrekkkker wet every day this week to drive out the gremlins
andrew
Andrew - the outcome of the Acrylic tests from our West Country laboratories
was sadly another failure:hammer:
So have you tried it???
Report please
Bonding this material is probably dependent on being able to wet the surface with the gluing agent. I have noticed that water will tend to bead on this material (PET). This is apparent both outside and (unfortunately) inside my soda bottle hull. So we probably need to do something to the surface to allow it to be wetted.
This may also have an impact on the surface friction with the water while sailing. Perhaps we should be painting the hull (but this wouldn’t help the bonding problem).
No Andy, I haven’t. Nothing in my range of model yacht interests suggests PET as a building medium. I did however drop an email off to the company asking about their recommendations for PET material glues, and will advise what (if??) I hear back in their response.
Regards
Dick I look forward to their reply with interest
I’ve been watching this thread & it occured to me to perform some actual tests of different adhesives. It would be easy to establish a fixed method of measuring (say 1 sq inch joint, weighted in shear) and compare different methods. Others could use a comparable method & results would have some empirical validity
RESULTS
-
“Marine Goop” Although it initially appear to have a good bond, it easily pulled apart in shear. What was interesting is that the inner parts of the bond were still tacky wet after 24 hours. This points out that the adhesive cannot rely on an atmospheric cure, as air will not pentrate the plastic. Conclusion : failure, although prolonged curing should be tried.
-
3M Brand 2 sided clear “Transfer tape”, commonly used in the printing industry. Weighted for several minutes at 8.5#, but failed in shear after “creep” occured with the tape/plastic joint. However, weighting at 5.5# has not failed a couple hours, with no sign of creep. UPDATE 7-24: The joint had separated when I checked it this evening, but I have no idea when. I would suggest the standard be minimum 2 hours without failure.
Conclusion: qualified success, as loads this size are unlikely to be found on the Footy.
Care should be taken that joints are not “tortured” together, in order to avoid creep/failure after longer periods of time. Another advantage is the “instant cure” time.
Below are pix of the test set up. Sorry, it was a real quick “quick 'n dirty” effort.
- closeup of the 2 pieces of 2L soda bottle, bonded 1 square inch, clamped with visegrip pliers.
- weight bucket,etc
- spare stones for weights
mmmmm, now that gets me thinking Bill, I sure that Andrew will be along in a minute to add his two penny worth in.
rgds
AndyT
Have you noticed how difficult it is to get the label completely off the bottle? Most of it is not glued at all, but it is glued at the ends with something that forms an indestructible bond. The answer may lie in this direction.
With regard to gluing PET, I have noticed something interesting. I am making some changes to my 3-Liter Torpedo, which required removing some of the tape which held the rear deck to the bottle. The tape is a cloth sail-reinforcing tape. This tape is VERY DIFFICULT to remove. It leaves a sticky residue stuck to the bottle, that can only be removed with a strong solvent (I have used lacquer thinner successfully, but with multiple applications). This implies that it is truly wetting the PET surface. This tape is probably designed to adhere strongly to PET, which I believe is the same as polyester sail material. If only we could find a glue made of the same stuff!
That, sir, is a brilliant insight. The Chif Chemist, Dr. Hastead is currently sitting in a tent somewhere in North Wales fending off rain and sheep. We shall see.
I have read all the posts & don’t recall sail seam tape being used/tested. It also comes in diff widths.
Even Martha Stewart used some type od double sided adhesive sheet material on TV show to cover a book. Try arts & craft store to find it.
I did try sail seam tape. It requires pressure, which may be hard to do when joining two fragile hull sections together. It seemed to work for a while, but eventually came apart easily.