baltic birch plywood

[donwatson]

Hi All,
I would like to raise a point here. Is there such a thing as Baltic Birch Plywood ??. In Scotland I have been looking for a supplier of baltic birch ply in 6mm (1/4") thick sheets. I have over time purchased from various suppliers/timber merchants 'baltic birch ply' and it has varied from the sublime to the ridiculous yet each supplier has stated that their product was baltic birch ply. I find it quite annoying to start a job with a new sheet and part way through cutting gears ( I build wooden geared clocks ) I find various voids that destroy the integrity of my work. Has anyone any experience of genuine Baltic Birch Plywood and where did they source it ???
Rant over

take care
Don W

 

[sunnybob]

There are many varieties of plywood.
https://en.wikipedia.org/wiki/Plywood#Grades

 

[AES]

As sunnybob has said, there are SO many grades of ply. Especially for cutting critical items like gear wheels you need absolutely perfect ply - i.e.NIL voids.

The only place I have found such stuff is either in model aero shops and at Hobbies Ltd. The sheets are quite small (about 12 inches x 6 inches) if I remember correctly, and in terms of price per sq inch, the prices are (I should say were, but bet they haven't changed much except upwards!) absolutely horrendous. But those sheets come in all thickness from below about 1/32 inch up to at least 1/4 inch (if not more, I can't remember) and at least these sheets are big enough for all but the largest gears I can imagine.

A word of warning if trying model aero shops - avoid what they call "Lite Ply" like the plague - it's just 3 laminations, the 2 outer being thin dark hardwood, but the (much thicker in proportion) centre lamination (core) being a VERY soft (& light ) white softwood (I think poplar). Obviously useless for gears.

OTOH I'm presently holding in my hand a small piece of the above "good" stuff. It's 0.8mm thick, has 5 laminations (yes, 5!) and is marked "Midwest Pacific, Micro Ply Beech & Birch Plywood". It's an off cut from an earlier project and I certainly did not find any voids. I also bet that if I cut the remainder into strips I still wouldn't come across any voids. It was imported into Switzerland from the USA ("Midwest Pacific" is a US model aero specialist) by my local hobby shop and cost 4 Swiss Francs - I can't remember when, but today that's the equivalent of about 3 quid. Prices of course go up according to thickness - as said, in terms of price per sq inch, they're really horrendous, but OTOH I've never, ever, found a sheet with any voids.

You can find your "local" model aero shops advertising themselves in mags like "Radio Controlled Model Aircraft".

Re Hobbies Ltd, I bought similar quality stuff from them but it's years ago now. But a quick web search will find them for you.

HTH

 

[donwatson]

Thanks for that information. My latest foray is to contact Heart Educational Supplies and order some ply from them. It is defined as 'Laser Grade' which I presume means that it uses softer glue that is cut easier by laser.
I have used Hobbies as a supplier of scroll saw blades and they are very good, I will have a look there and see what the ply is like.
I use a Stepcraft 420 CNC router/milling machine to cut gears and it does a good job.
I also have a 650mm x 500mm laser engraver with a 2.5 watt laser that I can cut through 1/8" laser ply so I am thinking of fitting air assist and trying some 1/4" Laser Ply to see if that is suitable.
I will let you know.
Don W

 

[AES]

OK Don, thanks.

Personally I've never heard of the Heart Foundation people as ply suppliers, but living miles away from UK what do I know?

I can confirm that Hobbies ply stuff was VERY good but having a good model shop just local I haven't bought from them my self for a long long time.

If you're "cheating" (laser cutting, not scroll saw!) then I wouldn't have thought the odd scrap gear was such a problem!

Seriously, if you do go the model aero shop route in future, as said I can't remember how thick that good ply goes (at least 1/4 inch, probably more) but in the past I have glued 2 pieces together to double the thickness. 24 hour 2 part epoxy (not the quick-set stuff for this job), spread out VERY thin and evenly (old credit card), a piece of poly each side, then the whole lot sandwiched between 2 pieces of thick MDF or something, clamped up and left at least overnight. Works fine (though - so far) I haven't cut any gears. Want to have a go - one day!

Cheers

 

[loftyhermes]

I've never had a problem with ply from Hobbies or SLEC, though I did by my last lot from SLEC but only because it was cheaper. https://www.slecuk.com

 

[donwatson]

The ply from Heart Educational Supplies arrived this morning, it was ordered on 15th June. 3 sheets of 6mm laser grade birch ply, there is a knot mark on the top sheet and a couple of butterflies on another sheet but I reckon it is all pretty usable, certainly good enough to cut gears from. The sheets are 600mm x 450mm x 6mm (pretty accurate 6mm). The sheets started at £4.51 each (£13.53) and with P&P + VAT ended at £21.03.

 

[AES]

Sounds pretty good Don, though not being in UK I can't judge the price.

Re loftyhermes comment, I must say that SLEC is a well known name in the model aero world, and in the past I've used them and their quality is (was) good. But I haven't seen their stuff here in Switzerland so my "knowledge" is not exactly up to date.

 

[donwatson]

I think the price is about average. The wood feels fairly heavy and it is 6mm plus or minus 0.04 where I could measure it. I am happy with it and will make a new start on a wooden geared clock that I made rather unsuccessfully just recently.
While I was on Hobbies web site there was 6mm wood in Mahogany and I think it was of a size I could use for my clock frames. I use 6mm ply for the gears as it stronger than 6mm wood in that situation but I think the wooden frame would like nicer.
I will start this project when I have finished my present project of a cougar head in Pyrography on a piece of 6mm plywood.
take care
Don W

 

[AES]

OK, thanks don. Good luck with both projects, and please don't forget, pix of both are OBLIGATORY!! ;-)

 

[donwatson]

Hi All,
I have finished the Cougar but not too happy with it. I may do it again on the reverse side of the ply. Not signed and dated yet as I will wait until Monday before checking it out adding any finishing touches.
I am about to start another 'burn' as I am not too impressed with the Cougar. I have had a bird house with a couple birds waiting to be burnt for some time now, it was thrown up in the clean out I had in the shed, quite a few things have surfaced during lockdown so plenty to do.
@AES, I remember the rule NPNH

 

[AES]

Well Don, please don't think I'm an expert ('cos I'm definitely NOT). Both pix are a bit "light" and out of focus, but despite that I think that cougar looks "not so bad". Perhaps the nose to back of the head maybe a little fore-shortened (?), and what's happened to the top of his LH ear?

But I certainly could not do so well (and I have no idea about laser cutting) so overall I'm pretty impressed. I certainly could not do so well with just my Ex 21.

Looking forward to seeing some gears.

And yeah, NPNH noted (NPNG?)

 

[donwatson]

Thanks for the comments. The pictures are from my Canon Ixus camera and are automatic. I may need to make some adjustments to the settings ??. I signed and dated it this morning and took a final picture.
I did this with a Davan burning tool by hand from a copied drawing but I may have printed the picture from the computer with a slight alteration of the perspective. I was not too happy with the results here so I am going to start another burn of a 'Winter Bird House' as the author calls it. I hope it is a bit better as it uses a piece of A4 ply and shouldn't take as long, probably a week given the time at my disposal.

 

[AES]

Re the birdhouse Don, that's going to look rather good I think. Best of luck with it. Apart from little use of a temp-regulated soldering iron with small tip I've never tried pyrography.

Re camera adjustments, again I'm definitely NOT a "proper" photographer. I think your Canon is a better make than mine (Sony - an old "bridge" model - i.e. halfway between a "point & shoot" & a "proper" DSLR), but I also usually also use the "general"/auto (standard) setting on mine.

However, although mine has anti-shake built in, I still always use a tripod or monopod. AND for close ups I have to go into the menu to re-arrange a baseline to change from the standard setting. In mine it's called "macro", and when working for a living I found that setting very useful for photographing documents clearly (usually less than A4 size). That setting also works well for close ups in my hobby stuff.

Whether or not any/all of that applies to your camera I dunno, sorry.

But there are members here who really are/can take pics "professional/ly", so if needed, you can always ask.

Anyway, I hope my comments weren't too critical - NOT intended.

Cheers