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  The Log; Part 1, Gluing the panels Using the "Z" press

 We begin with a stack of panels.. insuring the panels are in proper numerical order.. very important! There is a label on each to assist in that and also I found it pays to keep your eyes open and double check everything. Failure to do that cost me dear in one instance and succeeding at being alert saved me on another. More below on that. Notice the shapes revealed in the routing. There is a small bulkhead at lower left.
 The press comes from ATL and it's use is incorporated into the price of your panel purchase. The press surfaces are heated by water that circulates through the press heads. It needs several hours to warm up. Overnight is good. I set up a table to prep one panel whilst the other is in the "Z" press. After squirting the glue on both edges I spread with a paint brush as well.
 Next panel ready to be flipped over to match the other panel.
 Then push and wiggle side to side to evacuate any air and ....
 check alignment by the edge and... I found out later, keep an eye on the routed lines as well. Make sure those lines match as well as the edge. Those are Teflon coated press surfaces but when they get used a bit a spray of silicone does wonders.
 Then pump the hydraulic press to about 800lbs on the gauge and allow about one minute for every mm of panel thickness.

 Whilst the previous panel is in the press I squirt glue onto the next panel after dusting off any debris. Not everyone does, but I like to spread the glue after squirting on with a paint brush. The glue is two part epoxy with the container making the automatic allotment and the tip is the mixing devise.

This is also the time when I strip off the peel ply used as a masking surface.. see further below for an explanation...........

 I used a cooking timer and when the bell rings.. release the pump and raise the press and move the panel forward to prepare for the next one.
 Keep going.. and you will see the individual panels being revealed. Again, be careful to insure the panels are glued in the correct order. A note here.. the press isn't required for this job, it just makes the process faster. The heat makes the glue go off much faster. The job can be done with timber strips and screws to hold the lot together whilst the glue sets or see the link above on scarfing.
 My first bunch of panels were full length sections so I had a looonnngg section to push along before I could start cutting them free.
 The electric saw lasted about 10 minutes before it carked it.. did most of the panels with a regular hand saw. When sawing insure the surface facing the panel section is flush or even concave as a high spot on the edge of a panel will disrupt the fit when assembling.

 Tricks, Fixes and Problems
 I had some trouble pushing and sliding to get air out (as mentioned earlier) until there was a lot of panels to provide some weight. Couple of clamps took care of that.

 Here is the method that I was shown by a local builder for leaving a clean joint. Start by scoring a line in the peel ply parallel to the edge and full length.

For those that don't know what peel ply is... it is a nylon cloth that covers the panels to leave a clean and workable surface. When removed it takes contaminants with it that result from the curing of the resin and leaves a surface that doesn't require sanding for further work.

 Then squirt in the glue and spread with paint brush (I do anyway) and go through the pressing steps as described earlier. This is also a view of a perfect scarf joint. This is what they are supposed to look like. A good firm 'lip' on the fibre glass edge and the inside facing surface should be consistent, straight and cleaned off back to a few mm greater width then the fibre glass 'lip' edge.

 This is what it can look like then, after going through the press.

1. is a scoring line, this one covered in glue but no worries. Find a clean corner and pull the peel ply off.

2. the end of the peel ply. between 2 and 3 is where the glue will remain after stripping off the mask. 3.the edge of the 'lip' of glass.

4. the actual join of balsa under the glass showing the line of glue there.

5. the scoring on the other side. The peel ply will be removed between 5 and 3.

 With peel ply stripped away as described above, this is what you get. Very clean and easy to fair surface. BUT.. there is sometimes a but... this technique combined with some factory defects caused a lot of pain in the arse before the defects were spotted... more later.
 Sometimes the glue gun and mixing tip don't work well. Parts A and B are different colour and this shows inconsistency in colour indicating poor mix. I mixed as best I could on the surface with the paint brush and it seemed to work OK. just don't trust the gun.. always check.
 Here is where I had a win!! The panels were miss-aligned. If I had aligned in the press by the edge, which is the normal way, it would have been a disaster. But I had been watching everything by then and noticed that by aligning the edges the routed lines were just a little off.
 And again... after examining the thing I think I understand why it was done but to have shipped it off without alerting the builder to the anomaly was pretty slack.

This was a big awh SHIT! moment. Peel ply under the glued edge. Why? How? Answer... a variety of faults.

This join is ruined and will have to be ground away and redone leaving more fairing work. Of the 65 panels most had this problem to some degree. The first 20 or so panels were all good so this problem snuck up on me.

If I had used the method where you strip away peel ply prior to gluing the peel ply could not have got trapped under the glass but I would still have poor structural joints and the addition fairing.

 How did it happen???

Here is one way. The line in the peel ply was scored at the factory and was where the peel ply was meant to be removed but it wasn't. Even if I had removed adjoining peel ply before the gluing process this would have remained and caused the join to fail as the peel ply would have been under the glue.

Also note the inconsistent and ragged scarf.

   Here is another way... on this one the peel ply was scored and removed and the scarf was cut clean and consistent. But consistanly wrong! The under side was much shorter than the 'lip' side so once again, if not spotted there would be peel ply under the glue again.
 About 35 panels had problems related to poor scarfing. This was the worst but is a good indicator of one type of problem. The scarf is ridiculously over cut. There is almost no fibre glass left. Just a thread or two and the peel ply holding the lot together. This one was so bad someone at the factory appears to have covered it in clear packing tape so it would get here without crumbling more.
 an obvious need for better quality control.
   This is the most graphic example but so many had been over cut. Some would look OK at a glance but when closely inspected would reveal that most of what you were seeing was peel ply and little fibre glass left. This makes for a substancialy weaker joint. It would need to be taped and then the extra fairing.
 I had several (5 at last count) of these. Gross wrinkles caused by the resin going off whilst the panel was still being worked at the factory. The issues up front are.. heavier panels (resin rich) in what is supposed to be a light weight product, more fairing work and the peel ply can get stuck underneath the wrinkles and be very difficult to clean out, even requiring grinding off some glass to get it.
 More of same...

 So, the verdict so far....?

It's a good system but the poor workmanship of the panels has taken the gloss off. I am glad I didn't order the whole kit. I will finish in other material as was my preference at the beginning. I think a big part of my problem was that my panels were made just before the factory closed for the holidays. But if there had been one person at the end of the line with the responsibility of and authority for quality control this could not have happened. It's a high cost product. Hard to believe it has less quality control than a Chinese sock factory. Bob Oram, having looked through the lot and experienced with the product states that my lot was easily the worst he had ever seen, and my lot was small by comparison.

ATL when approached about this offered to give me a credit for merchandise of about $580 and an unspecified amount of tape and resin for repairs. Considering the cost was over $32,000 for this order I consider their offer meaningless. For you Americans... like leaving a 10 cent tip at a restaurant..

Would I do it again? Probably not. There are other materials and all of them are better and cheaper! If I did go with duflex again... I would require a contract that spelled out what constitutes a defective product to prevent misunderstanding. And.. I would go through every panel carefully prior to touching any of them. In fact, going to the factory to inspect prior to shipping would be a grand idea.


I ordered the panels before the holidays and was told the delivery could be after the middle of january due to closure for holidays. I told them i would really like to get them prior but if they couldn't, they couldn't. I had heard that they usually had a stack of rejects that one could get cheap and I wondered if maybe that lot were used to fill my order. If I had been consulted, I would have been OK to wait!!