Thread: Red Gum slab issues

hello Pete. I am a newby too but i have had a little experience with planeing red gum. It has a complicated cross hatch grain with tends to chip out whichever direction you follow the grain. I have had a bit of success levelling with a hand plane but sanding is the only way to finish it smoothly. An electric plane will always leave a square gouge which has to be sanded out so i don't recommend using one
I recommend setting a bench plane to as shallow a cut a possible and using a bow ground blade and winding sticks to sight the level. cut perpendicular to the grain in short passes with a firm lift at the end of each stroke. When your winding sticks say its pretty flat then use a really course grit on your belt sander also perpendicular to the grain. When that's done and flat now turn the sander to follow the grain.
Then a medium grit along the grain and then a fine grit. Don't use an orbital sander if you can avoid it as even fine grit will leave scratches in the really hard surface.
happy sanding. Oh and keep the sanding dust in a tin to use as a glued filler for any chips, splits and holes.

Years ago I had a red gum slab that had pretty much the same problem. I wound up fixing it in three stages. First I set up a jig for my router to run on and used it to level the entire surface of the slab. Then I went at the now level surface with various grades of paper in a belt sander. Finished it with a ros down to 1000 grade. It took a bloody long time but once it was ready for a finish it was smooth as a baby's bum!

Just a newbie here, but my short experience with redgum has taught me:

• You are going to be going for a hell of a long time to flatten it with a handplane, and an electric plane will be too uneven
• Although it will cost, perhaps look at discussing the issue with your local woodworkers - from memory, there are a few in Bungendore !!
• Alternatively, contact a timber retailer and they may have a thicknesser that can dress it down evenly - as long as one side is flat!

Otherwise, if you want to do it yourself, the plan above to use a jig and router to slowly bring it down would work. Slowly.

My 2c worth.

Hafgan

Originally Posted by Expat

Years ago I had a red gum slab that had pretty much the same problem. I wound up fixing it in three stages. First I set up a jig for my router to run on and used it to level the entire surface of the slab. Then I went at the now level surface with various grades of paper in a belt sander. Finished it with a ros down to 1000 grade. It took a bloody long time but once it was ready for a finish it was smooth as a baby's bum!

I may have to invest in a router. Never used one (I know!....its 2009), just never needed to as my house has very little timber (termite central).
How did you 'set up' the jig? What sort of a router bit should I buy?

Pierre,
You're not a million miles from Moss Vale where there is a company that has gigantic drum sanders.They usually flatten compressed fibrous cement or some such, but studenta from Sturt School of Wood at Frensham in Mittagong, go there to get larger work pieces flattened.The cost is very reasonable.
Be warned though.They are a sincerely Christian family, and the SLIGHTEST profanity or blasphemy will result in you being shown the door.
Jim

Originally Posted by Lignin

Pierre,
You're not a million miles from Moss Vale where there is a company that has gigantic drum sanders.They usually flatten compressed fibrous cement or some such, but studenta from Sturt School of Wood at Frensham in Mittagong, go there to get larger work pieces flattened.The cost is very reasonable.
Be warned though.They are a sincerely Christian family, and the SLIGHTEST profanity or blasphemy will result in you being shown the door.
Jim

Yep. Can't remember their name, but they manufacture floorboards and other stuff (not fibrous cement as far as I know). They can do coarse & fine sanding in one pass, up to at least 1200 wide. Price is reasonable.

I've never used it, but have had reports of redgum slabs moving and deforming the rest of the kitchen as they go. Be aware.

I'll call the Bungendore Woodworks tomorrow. I have lots of friends who work the counter.

Failing that...Just over an hour to Moss Vale. Good plan Jim. I have friends up there I can visit also.

Pete

Originally Posted by AlexS

Yep. Can't remember their name, but they manufacture floorboards and other stuff (not fibrous cement as far as I know). They can do coarse & fine sanding in one pass, up to at least 1200 wide. Price is reasonable.

I've never used it, but have had reports of redgum slabs moving and deforming the rest of the kitchen as they go. Be aware.

Alex,
This slab will be set alone as a breakfast bar. It isn't going to be attached to any kitchen cabinets, if it does twist or warp any more it will become a feature (That's what I'll tell the minister of housewives)

Pete

Jim,

Is it Coach House Timbers? Had a look in phone book.

Pete

Sorry, I don't know the name of the firm, but if you give Sturt a ring they MIGHT be able to help, but the Director is severely unwell, and this year's classes probably haven't started.
Your mates @ Bungendore Wood Gallery might be able to put you in contact with one of the Sturt ex students that exhibit there.
Hope this helps,
Jim.
PS, I'm sticking by my claim that the firm DOES work concrete slabs.

Originally Posted by Luckypierre

I may have to invest in a router. Never used one (I know!....its 2009), just never needed to as my house has very little timber (termite central). How did you 'set up' the jig? What sort of a router bit should I buy?

Well the jig I built rolled along on the mdf top I secured to the workbench so it was dead level and smooth. That's something you have to be sure of from the get go. I used 4 industrial casters - fixed, not swivelling - to support the frame for the router. This frame bridged the slab and was built so that it barely cleared the slab surface. It was made from 1" formply. A bit of overkill I know but I wanted it to be solid. The router had a 3/4" collet so it would slide from side to side across the frame of the jig using a 2" flat bottom bit I think I got from a friend of my dad's who was a cabinetmaker out Carindale way. What brand it was I honestly don't know. I'm pretty sure if you can't find one listed by any of the major manufacturers there are companies around that will make you a large flat bottom bit. It took me a lot of passes to get the thing level but once the worst of it was done it was a simple matter of changing to a new 1" bit and making a series of very light passes just to give it a finer cut before I laid into it with the belt and then the ros sanders.

ps What's up with the forums today!? Someone do an update or something?

Don't think it's Coach House timbers- could be Southern Trade Supplies, from memory they are in that area.
Try Sturt - one of the teachers who was helping out last year, James or Stuart, may be able to help if they are around.

Evan Dunstone in Queanbeyan may be able to put you in touch with someone closer who can help you out.

if you can find someone up your way with a slabmaster they can level the slab for you ,this should take around 30 to 40 minutes then get it put through a good drum sander this way it will be level and flat all up i would charge around $120-$150 the slab should end up around 40mm-45mm thick if you want to go down this track pm me and i'll send you the number for the bloke who makes the slabmaster and he should be able to put you in contact with someone in the local area .all this i think is a lot easier than router jigs and finish sanding (just my opinion)

The Company is Highlands Timber Coating 02 4869 1488. they have a number of very large drum sanders and can take a slab down to 400 grit if you wish. They do good work, are reasonable with pricing, and are very nice people to deal with.

If you want to get your slab truly flat You will have to start with at least one side reasonably flat, as the drum sander will use one side as a reference surface.
It may be that the moisture balance across the section of the slab is uneven, this can be corrected by wiping the concave side with a cloth soaked in water, which will cause the slab to deflect back, support the slab on timber slats around 25mm thick every 250 mm or so along its length, and monitor the movement of the slab over a period of several days.
Alternatively you could make up a jig using a sheet of 18mm ply, and a series of screws in the ply so the slab will sit level without rocking or flexing under the drums, until the drum sander flattens one side, then you can proceed from there.

Once you have got it flat it is guaranteed to move it is a question of by how much and you will have to build your bar to hold it flat but allow movement across the width.