Build tables

aussiesteve

Well-Known Member
I have a renewed interest in Kit building and as a result am resetting my table .
Last time I kit built, the table top I used was 2.4 m x 1.2m (8' x 4') and was topped with cork tiles. Due to wear and tear, that is pretty much no longer useable now so I am figuring on using my "ARF assembly table" and putting a new surface over it. It is 3.6m x 1.4m (~12ft x 4'6") and built out of a Melamine kitchen bench top that is 40mm (1 1/2") thick. Problem with it is that it has a slight bow in it (It sags in the middle by 1.5mm ~1/16"). The corners are all level with each other, it is just the sag that concerns me. I am trying to shim the centre up but it doesn't seem to wish to get any better than that.

So here are my questions

1 - How much sag would be acceptable to you?

2 - What to use to top the table with?
I am considering
Gyprock (Drywall) (there are sheets readily available that will fit this well), Cork tiles or Foam as all of these readily allow pins to be used. I have also considered a metal top so magnets can be used.

Ok - looking for advice here.
 

BRUTUS

Plank Junky
Lifetime Supporter
The foam is pretty soft and doesn't hold pins well- plus, if you put any weight on it you will leave a dent.

1/16" sag in 8' is negligible. My plans from BUSA have almost a 1/8" deviance in 5' on the straight parts.....

As far as shimming a piece of material as thick as your ARF assembly table, it would need to be supported all the way to the floor in the center to counter the effects of gravity, and the weight of the rest of the table should be bearing down though that center support, essentially lifting the other 4 corners lightly off the ground. Thus, reversing the effects of dead-load over time. If the top is unable to be straightened using it's own weight then I would weight the ends and lift the center until you get it straight, then use mechanical fasteners to hold it there.

Best of luck-

I had a friend obsessed with a *PERFECTLY* flat table. He drove himself nuts trying to get it down to .008" He eventually gave up and hasn't built a kit since.
 

Flatspinjim

Well-Known Member
1/2 inch plate of glass works well with drywall over top of it. I get pretty obsessed with a flat table too.
 

aussiesteve

Well-Known Member
The table has got 6 legs, including a set in the middle. The centre set of legs were added after the sag took place. (about 2 weeks after I built the table at the height of summer here). At the time, I wasn't too bothered about it because for ARF assembly, it was fine. That inital sag was actually about 1/8" because I didn't quite get around to finishing the frame when I first assembled it. I'll take some photos of it tonight.

We are in a heatwave here at the moment so I am hoping the heat will work in my favor to get the shimming to help. I am thinking of building a hot water pool on top of it with some timbers and a tarpaulin and filling it with hot water (tap water) to accelerate any help the heat may give. It will either work or be a spectacular failure I guess.

The only problem I have with a plate Glass top is unless you use the drywall ro similar (in which case the glass is not really required if I can get the top acceptably level) what do you use to clamp / Pin parts to the plans with? or do you simply not bother?

I have tended to avoid the foam in the past for the reasons you have mentioned.

The first kit off the rank will be a Profile kit that I have had laying around for a few years now (MoJo 65 to replace the one I recently broke).

Best flat table I ever used is the Marble block surface table in my factory. It is a little small for the kits I have in mind (1/4 and 1/3rd scale mostly) and whe I used it for that purpose, the guys in the factory kept hinting to me that they would like to use the table (They haven't got the guts to tell me outright though - sometimes it is good to be the King :prrr:).

I wouldn't have the problem if I had built and finished the frame for the top properly when I first built it :banghead:- but I was in a hurry to assemble an ARF at the time. I got the top as a "second" from a factory that makes them, It has a little crack in one corner on the underside (it is completely wrapped in Melamine) and cost me about $50 or less from that factory.
 

Revy

K, letsgo!!
Scavenge through your metal recycling place. You might find and old map table/cabinet or security cabinet door. I did and got a metal map table top. Reinforced, melamine top, magnetic and flat! Size is a bit of an issue, though, as it is only 70 inches long and three feet wide. A pair of sawhorses makes it portable too. ;)

My latest project is an S'bach3D 65...
 

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aussiesteve

Well-Known Member
Excellent idea Revy.
In reality, I don't need the full top of my bench for any kit that I am likely to build. The biggest I am likely to build will be around the size of a 1/3rd scale BUSA kit of some sort. then again, I have previously built a very early concept of the WWRC "85cc" profile (I bought the oversized ribs from Richard a while back and made up the rest from oversized plans of the 50cc).

Is that SBach one of WWRC's?

I am only doing the 65" that i am doing because I had the kit sitting here already (I bought in a few of them a couple of years ago and had 2 left over). I am trying to decide whether to install my spare Mintor 22 (it has the good piston / cylinder combo in it) which will require some mods to the front or a Saito 1.25 that I have laying around or an OS RX 1.40 that I also have here (It has a 2 glowplug head on it just for something different) or a YS 1.40 that I have sitting here. So many choices - do I go slimy with little work (and good power or ballistic over the top power) or clean with a little more work :crazy:
 

Revy

K, letsgo!!
It's Ron Wilson's. For some reason, Richard wouldn't ship to me. The Balsa store was carrying them as kits, but I dunno about that anymore. I'll email you some info.

As for the table, it has worked out well for me. ;)
 

aussiesteve

Well-Known Member
I did a little more work on the bench last night. After the heat yesterday combined with some weights (aka 10 gallon containers of water strategically placed on the bench) and the shimming, I now have the bench within 0.5mm longitudinally (not bad - 0.020" in 12 ft - I can live with that) Problem is, I have about 1mm (0.040") Laterally (the short side) but that is even along the entire length of the bench and less of an issue to deal with during building.

Because this table gets used mostly for assembling ARF's or maintaining planes, I am thinking of making a removable top for building. I am currently thinking along the lines of either 2 or 3 pieces of 1/2" MDF that I already have here topped with cork tiles or a sheet of drywall. I can then shim those pieces it as required for flatness when I install them for use in case the top bows on me again.
 

BRUTUS

Plank Junky
Lifetime Supporter
I'm starting to appreciate how useful a magnetic building table could be. I wish Great planes still made their magnetic building system- I'd buy it for the magnets, squares, and clamps. If I were building professionally I would definitely have an 8' long 3' wide magnetic building bench. Stabbing pins through the parts you are trying to stabilize and hold introduces too many twisting moments and un-even holding ability for my taste. But, I guess spearing pins through the parts will have to do. That's how grandpa did it, and it seemed to work for him!

Look what I found...

http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/tools/magnetic_building_board/order_magnetic_fixtures.htm

DROOOL! Reminds what it felt like when I was a kid with a new erector set... I want one for geek factor alone.
 

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JohnBer

Well-Known Member
built my table frame from some 8 foot pallets we got at work. Ironwood they call it, think its just a low grade oak. trued it up on the table saw and went and got a piece of 1 1/8" particle board. it came out really flat. no light under a strait edge at any angle. I did goof tho, made it 6X4 should have made it a foot longer. thing weighs about 300 pounds is the big disadvantage. i add a peice of drywall to the top when building.
 

Dookieshoot

i love farts
I've built a bunch of tables now...for myself and friends. I kinda enjoy it actually. The table I use for buiding, yes i'm lucky enough to have specific tables, is 3 1/2 wide by 8. I used cheapo 2x4 poplar from home depot, but engineered it to be strong as heck and not move around a whole bunch when the seasons change. Gussets everywhere, and extra legs in the middle! The top is 3/4 marine ply, use lots of screws!

Now, this as it stands could be used as it came out pretty dang close to flat....but I'm a total tard and like to re-engineer the wheel. I feel after time it would walk around, and I never build anything quick. (other than tables) Enter the mighty oak. So, another trip to home depot yeilded a SOLID CORE, heavy ass oak door. These things are super flat, and very smooth. But how do the pins stick in? Drywall! A slice of 1/2" was cut to the door size and laid on top. I don't recomend screwing the door or rock to anything, it's all heavy enough that it isn't gonna go anywhere and my feeble mind tells me it's better off that way. The drywall has a beveled edge remember for tape, mud, ect remember. I left it on there...I didnt want a dusty white line across my gut whenever I'm down there leaning over reaching for my beer. It takes pins fairly well, just use "t" style as they can be a little hard to get in otherwise. I've been using this set up going on it's third year and it's still good and flat.....however it's always a friggen mess down there. Need more shelves!!!!!!!!!!!!!!!!

Good luck
 

aussiesteve

Well-Known Member
Today I get my son to pick me up a sheet of Drywall (We can pretty much only get 3/8" here) and I will be building tonight.
Table is good enough for anything I am likely to build. I might not have mentioned before that I am using a 3 meter long straight edge and a Laser Level (just for fun - definitely not necessary) to check this so the measurements are over the whole lenght and width of the table. The sag is even all the way along and all the way across.

I like to have a large build table so that I can make a number of parts at once and have the glue curing overnight. For example all the wing sections of a bipe in one hit. I am also blessed with a lot of room in my shop (60 ft x 30 ft - purpose built just for my hobby) so space is not an issue.

I have another table that I use for cutting covering on. It's an old kitchen table. I also have a few of these folding trestle tables which come in pretty handy to have around. (Especially for the beers).
http://www.bunnings.com.au/products_product_table-blow-mould-marquee-183x76x73cm-steel-80248_P3191115.aspx?filter=categoryname--Outdoor+Tables

My big table is also waxed regularly with Fibreglass release wax (traffic wax style) - it helps considerably to keep it clean when glue gets dripped accidentally.
 

aussiesteve

Well-Known Member
I like the look of that building system Cody. Reminds me of my Childhood - Meccano.

I considered turning this into a magnetic table but decided against it. The magnets are pretty readily available fom the Welding suppliers and good stationery stores.
I use T-pins and I also have a buddy who works at a tyre shop. He gives me all his old wheel weights and I melt those down into various sizes of weights for hold downs.

It is difficult to get wide rolls of clear wax paper here so I use clear Polyethylene Builders film over my plans. (I buy rolls of 20 micron when I see them available). Another cheap cover I have used is clear painters drop sheets.

Hopefully I will be able to take a photo of the table set up and in use this evening.
 

BRUTUS

Plank Junky
Lifetime Supporter
I'm sold on painters plastic instead of Wax paper- the glue doesn't even stick!

If I were building professionally I would definitely invest in one of those magnetic build systems. Freaking awesome!
 

CanCanCase

Well-Known Member
I'm not God's gift to RC or anything, but I've picked up a few great tips from all this interweb reading...

First, for a table: I've had tables made out of door blanks in the garage since I was a little kid. My Dad's been building on sawhorses, pressboard shelves, filing cabinets, dining room tables, and so on...all topped by a door and some pin-holding surface... since about 1981 - and that's just what I can remember as a kid!

I'm also in the laundromat business, so any time I buy a place, they've got these crazy sturdy, melamine topped tables for folding clothes. I've got 2 in my shop right now and am kicking myself for not dragging a third home. Width varies depending on the layout of the washeteria... typically they're 24" - 36" wide, and 4, 6 or 8 feet long.

Next is the pin-holding surface... I've cut a sheet of Cellotex to fit my bench top. It's the stuff acoustic office ceiling tiles are made of, but if you buy ceiling tiles, you get 3' sheets, and at our local builders' supply if you ask for Cellotex it comes in 4'x8' sheets. It will cut easily with any saw, but do it outside... fluffy paper/wood/pulp mess!

Ron Wilson showed me a neat trick over at the PB site... instead of pinning everything to the board, and working out all the twisting and crushing forces that come with my fat, meaty hands, I went to the local industrial metal shop and had pieces of 1" steel key stock cut to length... I've got a set of 2", 3", 4" and 6" pieces on the bench right now. With a little effort with a file, the ends are now nice and smooth, and the key stock is perfectly square. One on each side of a rib holds it up perfectly square. A few holding things up square and a few on top to hold things down flat works great for just about any size build. The framing on the WWRC 50cc has been done with no pins at all - well... I cheated and started pinning sticks to build the ailerons and elevator! But wings and fuses with 90-degree formers are a snap with these steel weights.

-Case
 
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