The Framers Forum

Hi- looking for advice- I use a mitre saw and then a morso to cut the mitres - blades are sharp and I clean them regularly with a soft cloth. I also use a digital angle finder to make sure the stock and blades are at 45deg.

I check lengths for accuracy.

Then I’ll use mitre bond (2-part) to join 2 ‘L’s’ before underpinning using the alfamachine u200. Then I’ll join the 2 ‘L’s’ on the underpinner.

Problem is I can see daylight- usually much less than 1mm and I can of course fill it with frame putty - but I’d rather not use FP at all. Am I being too unreasonable on myself or am I missing something fundamental?

Any advice please?

Thanks
Dave

No you are not being unreasonable, as far as I am thinking frame putty does not add any worthwhile strength to the mitres and also it is added extra labour time to producing the frame. Could the problem have anything to do with the setting of the fence angles on you Morso?

I would try using a wood glue like Titebond instead of Mitre bond which is a type of superglue.
My understanding is that the underpinner wedges are to hold the joint in place whilst the wood glue goes off. I think in your case the mitre bond will set immediately and the wedges will then break the join.
You don't say what wood type you are joining. Are you using the correct wedge type for soft or hard wood timber?
If you are joining Oak or Ash, these can be extremely difficult to join on an underpinner, imho.

There are some glues that expand as they cure. Polyurethane for one. The stuff you are using might do similar.
These glues are very strong, but need to be firmly clamped. The V-nails in poly moulding don't have the same grip
they have in wood. You may need to clamp the frame in a band clamp after gluing and before pinning - which is a
big faff. I would try different glues as my learned colleagues have suggested.

Can I ask two questions on this? You use a mitre saw and then a morso to cut the mitres. Is there a reason for that?
Second question, on the mitres joined by mitre-bond glue, can you see a gap on those?
I'm making guesses here but 99% of the problems with mitre gaps are down to the cutting.

Sorry, I mean when you first join up the L's before underpinning. I'm presuming the mitre-bond glue is that instant grab stuff.

Thanks for your feedback so far.

Titebond - got
Mitre clamps with deep and wide jaws - on order

I use the compound mitre saw to rough cut to length and then trim on the morso

I’ve checked the morso blade angles with the digital angle finder so I know it’s at 45deg.

The trouble could be that the opposite sides may be slightly different length this when the four corners are clamped a small gap is obvious. We’re not talking >0.5mm but it’s enough to need attention after underpinning.

I suppose the follow up question might be how do I make sure I’m getting exact replication of side lengths- I have a ‘right arm extension’ (but not used due to space) on the morso but nothing on the left side.

Further comments and feedback welcome

Oh dear! That's enough to cause serious problems. I think you may have just explained why this is happening.

Is that the extension on both sides ?

It is much easier to work with both extensions.

Thanks for your replies everyone- the penny has dropped and I’ve already seen some improvement- closing in on as perfect I can get
Cheers

It will all become an instinctive thing after a little. There usually a bit of a learning curve when we first get started. Much of the difficult stuff becomes quite easy after a little while.