Glue for form ply for sp10 plinth?

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cafe latte
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Glue for form ply for sp10 plinth?

Post by cafe latte » 12 Jun 2014 02:53

Ok it is finally going to happen, I have been too busy to get round to my sp10 plinth and the air arm project ran to a grinding halt too. The cow are moved to the back paddocks, the weaners are separated, I still have some weed checks to do in a few weeks but things should finally get a bit calmer. Anyway back to the sp10, I have considered many different woods and ply for the plinth and the best by far would be form ply which here in Aus is made of hard wood and it is seriously heavy, ideal for a TT plinth. There is though one problem, form ply is coated with a non stick coating sort of a brown paint so the form ply does not stick to the concrete when making forms. My worry is this paint wont glue very well, removing it is an option, but I wondered if anyone has tried gluing form ply as it is?
Any tips for an sp10 plinth would be welcome.
I am still unsure too if a separate are board is really needed and if so how best to construct/ isolate it. How is the arm board on the original Technics plinth, is it isolated or is it just bolted to the plinth?
Regards
Chris

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Re: Glue for form ply for sp10 plinth?

Post by bra10n » 12 Jun 2014 03:40

Hi Chris,
The coating on form ply is actually a formaldehyde impregnated 'paper'. It will stick face to face with a similarly based formaldehyde resin, but may I suggest two alternatives for your consideration. Your locality necessitates an 'A' bond glue line found in structural plywoods and of course marine ply. The cost of marine ply is exorbitant but it does offer two very good faces to work with and is flat, unlike structural ply. You may be able to minimise costs to a degree by sourcing offcuts possibly from local boat builders or the like. It should be number 1 and 2 on your list for the intended purpose. Your other option is an imported hardwood ply, also with an A bond glue line and most commonly made of Mersawa or Melapi. If you go this route, be careful with the Melapi product as ply from it is sometimes constructed with a 'B' bond at best, but most commonly with a 'C' bond.

'A' bond - an industry standard of *24hr boil test.
'B' bond - *7 hr boil test.
'C' bond - *1 hr boil test.

* This is before delamination of the ply occurs.

Here's a link that may help;
http://www.gunnersens.com.au/products/b ... ywood.html

FYI A/C and B/B are plywood face grading's, obviously A/A is premium grade, marine for example.

HTH

cafe latte
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Re: Glue for form ply for sp10 plinth?

Post by cafe latte » 12 Jun 2014 04:05

Hi Bryan,
Thanks for that, what sort of formaldehyde resin, do you know a brand name? Are there any other glues that will stick to it?
I thought about form ply as when I did my other ply plinth all the other types of ply are much much lighter and even the hardwood plys have softwood layers unlike form ply. I would also want to stick a veneer layer on the top as brown paint is not very fetching :D
Regards
Chris

Alec124c41
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Re: Glue for form ply for sp10 plinth?

Post by Alec124c41 » 12 Jun 2014 04:13

How about using a belt sander to remove the coating? Outdoors would be best.

Cheers,
Alec

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Re: Glue for form ply for sp10 plinth?

Post by cafe latte » 12 Jun 2014 04:21

Alec124c41 wrote:How about using a belt sander to remove the coating? Outdoors would be best.

Cheers,
Alec
I did think of that, but the surface is so super smooth if I could find a glue to stick it as it is it would be easier. I wonder though if paint stripper might shift it?
Regards
Chris

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Re: Glue for form ply for sp10 plinth?

Post by Alec124c41 » 12 Jun 2014 04:22

Worth a try.
I was thinking of #40 grit.

Cheers,
Alec

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Re: Glue for form ply for sp10 plinth?

Post by bra10n » 12 Jun 2014 04:28

cafe latte wrote:Hi Bryan,
Thanks for that, what sort of formaldehyde resin, do you know a brand name? Are there any other glues that will stick to it?
I thought about form ply as when I did my other ply plinth all the other types of ply are much much lighter and even the hardwood plys have softwood layers unlike form ply. I would also want to stick a veneer layer on the top as brown paint is not very fetching :D
Regards
Chris
Structural plywoods manufactured to AS/NZ standards and graded with an "F" number by law cannot use a mixed species within its construction. You most likely compared form ply with a softwood (pinus) based structural ply. That's why I recommended hoop pine as in marine (an exception to the rule) and those imported hardwoods.

The issue of weight is a consideration for your plinth and I do understand that. However another consideration should be species and construction density. The density and grain construction of the timbers I suggested will avoid the lifting and splitting so often seen in cabinet work exposed to harsh environments. And of course, the higher the grade of plywood ensures the fewer hollow 'cores' are found. A stipulation of marine ply is 0 core spacings in fact.

Brand names I'm sorry I can't help you with... 200 litre drums are all I was used to.

Again boat builders may prove to be your best friend...

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Re: Glue for form ply for sp10 plinth?

Post by phonomac » 12 Jun 2014 08:05

Depending on availability in your part of the world I would recommend looking at Multiplex MU25. It is made by the same manufacturer as Panzerholz (Delignit gmbh) and is a pure beech ply made by laminating under heat and pressure to achieve about 20% compression (similar process to Panzerholz).

It is about one fifth of the price of Panzerholz here in the UK, and provides a significant proportion of the benefits of Panzerholz. I have had good results with a plinth for a Lenco and am currently doing one for an SP10.

Hope this helps

Angus

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Re: Glue for form ply for sp10 plinth?

Post by cafe latte » 12 Jun 2014 09:09

I am off to town tomorrow and there is a wood yard who can order most things I will ask what they can get so any other possibilities please post :D
Regards
Chris

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Re: Glue for form ply for sp10 plinth?

Post by cafe latte » 12 Jun 2014 09:10

phonomac wrote:Depending on availability in your part of the world I would recommend looking at Multiplex MU25. It is made by the same manufacturer as Panzerholz (Delignit gmbh) and is a pure beech ply made by laminating under heat and pressure to achieve about 20% compression (similar process to Panzerholz).

It is about one fifth of the price of Panzerholz here in the UK, and provides a significant proportion of the benefits of Panzerholz. I have had good results with a plinth for a Lenco and am currently doing one for an SP10.

Hope this helps

Angus
Thanks Angus,
I will ask tomorrow. What are you doing re the arm board in your design?
Regards
Chris

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Re: Glue for form ply for sp10 plinth?

Post by cats squirrel » 12 Jun 2014 18:17

Hi Chris,
as you know I test a lot of materials for suitability for plinths, but I have not come across this form ply, so cannot comment. But Haydn (from Brisbane) sent me a piece of Permali, which proved to be very suitable, if hard on tools. Similar to Panzerholz.

One problem with thick plinths (to make up a high mass one) is that as the thickness increases, the critical frequency decreases. And mass is only effective between the fundamental resonance frequency and the critical frequency of the structure in question. That means, as the number of layers increase (to add mass) the critical frequency decreases, until the thickness is too great, and mass has no positive benefit, whatsoever.

I don't make thick plinths, in fact, for Lenco's (my preference in my price range :( ) I make what I call picture frame plinths, like the original Lenco chipboard plinths. Here I use hardwood from your neck of the woods (no pun intended) like red ironbark, jarrah and buloke (if I could get it!). Ipe is also good, if it doesn't split and warp, as mine did! Resinated bamboo is also quite good if solid (some is not).

My latest Lenco plinth uses a frame made from a composite of Al/HDPE/Al, PVC and acrylic, all glued together. Corners are made by overlapping. Details later!
HTH :D

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Re: Glue for form ply for sp10 plinth?

Post by bra10n » 12 Jun 2014 21:24

The hardwoods you've mentioned with the exception of Ipe grow in the most arid of environments and is the contributing factor of their hardness though substantial variation is still possible due to unseasonal weather conditions and culling/milling techniques. Their durability and density is down to an interlocking grain weave primarily.

The commercial species namely Ironbark and W.A Jarrah have been air dried (sometimes for as long as 8-10 years) before they are milled. Exotic timbers (legally felled or otherwise :shock: ) are shipped/traded accordingly. Removing them, and generally any timber from its 'natural' climate, is a chance affair as warping, bowing and peeling can often be the result.

cafe latte
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Re: Glue for form ply for sp10 plinth?

Post by cafe latte » 12 Jun 2014 23:01

bra10n wrote:The hardwoods you've mentioned with the exception of Ipe grow in the most arid of environments and is the contributing factor of their hardness though substantial variation is still possible due to unseasonal weather conditions and culling/milling techniques. Their durability and density is down to an interlocking grain weave primarily.

The commercial species namely Ironbark and W.A Jarrah have been air dried (sometimes for as long as 8-10 years) before they are milled. Exotic timbers (legally felled or otherwise :shock: ) are shipped/traded accordingly. Removing them, and generally any timber from its 'natural' climate, is a chance affair as warping, bowing and peeling can often be the result.
I did think about Ironbark simply because my property is covered in it along with other species. My friend has a portable mill too so getting wood I can use from a fallen tree is not a big problem, but I was feeling a bit lazy, making my Commonwealth plinth was a royal pain in the butt. Each layer had to be clamped down for days as it kept wanting to warp. I thought about ply this time as the basic plinth shape can be knocked up in a few hours then a few hours over the next few days doing the finish. Hmm what to do..?
Regards
Chris

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Re: Glue for form ply for sp10 plinth?

Post by cafe latte » 12 Jun 2014 23:06

cats squirrel wrote:Hi Chris,
as you know I test a lot of materials for suitability for plinths, but I have not come across this form ply, so cannot comment. But Haydn (from Brisbane) sent me a piece of Permali, which proved to be very suitable, if hard on tools. Similar to Panzerholz.

One problem with thick plinths (to make up a high mass one) is that as the thickness increases, the critical frequency decreases. And mass is only effective between the fundamental resonance frequency and the critical frequency of the structure in question. That means, as the number of layers increase (to add mass) the critical frequency decreases, until the thickness is too great, and mass has no positive benefit, whatsoever.

I don't make thick plinths, in fact, for Lenco's (my preference in my price range :( ) I make what I call picture frame plinths, like the original Lenco chipboard plinths. Here I use hardwood from your neck of the woods (no pun intended) like red ironbark, jarrah and buloke (if I could get it!). Ipe is also good, if it doesn't split and warp, as mine did! Resinated bamboo is also quite good if solid (some is not).

My latest Lenco plinth uses a frame made from a composite of Al/HDPE/Al, PVC and acrylic, all glued together. Corners are made by overlapping. Details later!
HTH :D
Hi Cats I cant wait to see your finished plinth :D I did not want a big thick plinth this time anyway as I think the sp10 lends itself to something more sleek.
Before i posted my question here I was fairly sure what I was going to do though, now I was more confused than ever :D
Anyone have any thoughts on the armboard?
Regards
Chris

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Re: Glue for form ply for sp10 plinth?

Post by bra10n » 12 Jun 2014 23:31

Personally if I was looking for a straight forward build I'd be using the Hoop Pine with an A/C face from the link I posted above or similar. Ultimately the decision is yours but as the plinth will be veneered I think you'll appreciate the flat and stable substrate when you reach that stage. From memory 9mm thickness is a 7 ply, 12mm 9 ply.

I have no affiliation with the company but I have used them before and I know as a wholesaler they are 'distributor' orientated... just how near to you is the question. Otherwise search out Austral Plywood distributors in the far north.

Best wishes

Edit: Noticed your question on the arm board...

Not sure what design you favour but ply would allow you to customise each plywood layer as you're building the plinth leaving you with something like a drop-in panel that can be fixed with screws...
If you were buying flitch (veneer) you might also consider buying an additional matched leaf section from which to cut the veneer from for the arm board so it grain matches when assembled.

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