MatthewRedStars
Established Member
Something i finished recently, had enough interesting problems with it to stick it up on here... these included problematic mitres and ammonia fuming.
The main carcass is made from oak faced MDF (19 mm sides, 6 mm back) panels in an 40 mm frame.
To make life hard for myself i decided to chamfer the face of the frame into the doors (ie. i reduced the 40 mm frame down to 20 mm for the doors so the doors appear set back in the chamfer).
Here i had two options:
1) use mason's mitres to make the frame joinery easier but then have trouble cutting the chamfers (I couldn't just whiz them on the band saw with a mason's mitre).
2) use 'normal' mitres for the frame, complicating construction of the frame but meaning that the chamfers would be easy to do.
I chose option 2. I cut the chamfers on all the face pieces on the bandsaw.
I then started to cut the mitres on my chop saw. They were rubbish. The cut wasn't square or accurate, I think the blade wasn't thick enough to resist wandering. Or maybe there was too much play in the saw. Either way they were poor. Onto the sliding table of the table saw. Rubbish again, this is a far east saw and, while it is excellent as a rip saw, the sliding table has so much play (that i've spent hours trying to correct) that its useless for cross-cutting.
In the end i had to make a mitre jig which ran along the rip fence. This was simply a sheet of MDF about 18" by 24" with a solid fence screwed and glued at 45 degrees. As i had thoughtlessly already cut the chamfers i needed to make L and R hand versions.
Success at last!
The mitres were clamped up and drilled and pinned from the top and bottom with dowels, two per joint. The dowel/holes will be hidden by the plinth and top.
The glue up of the face went swimmingly.
The glue up of the back and sides went swimmingly...
....except that when the mitred face was attached to the rest of the frame, the mitres opened overnight (creating 0.5 - 1 mm gaps on three of the four corners). I believe this was due to the use of softwood dowels which simply couldn't resist the stresses of the frame.
I'm not sure of a better way to do this without more complicated joinery. Biscuits? Hidden screws even? Anyway lesson learnt!
I was pretty gutted. In the end i had to handsaw out the mitres to an even and regular gap and add shims. I was disappointed but to be fair i'm sure maybe 1 out of 10 people would ever notice and only a few of them would care. The shelves and plinth were 19 mm MDF lipped with solid. The legs, apron and top were all solid.
As an experiment, and to avoid using a stain i decided to fume the oak.
I made a frame from cheap 44 x 20 mm battens and covered it in a giant plastic bag from a bed that had just been delivered along with lots and lots of gaffer tape. I poured some household ammonia into a baking tray and slid it inside. I was worried that my weak ammonia wouldn't be effective but i was too scared to use industrial stuff! I was pretty careful with the household stuff but the smell was by no means excessive and in the end i was worrying about gasing myself for no reason.
I left the cabinet in for about 24 hours. I took a breath, ripped open the plastic, poured the ammonia into an old plastic tub and put the lid on. I then left the workshop for a couple of hours! The cabinet had a unattractive gray/brown tinge when removed but a quick wipe with white spirit showed a lovely rich brown colour. The cabinet was finished with a few coats of shellac to give an open grained low-gloss finish.
Photo by Phil Faulks (wild7.co.uk)... i'm not sure about the white background, would just a sheet look more natural?
The main carcass is made from oak faced MDF (19 mm sides, 6 mm back) panels in an 40 mm frame.
To make life hard for myself i decided to chamfer the face of the frame into the doors (ie. i reduced the 40 mm frame down to 20 mm for the doors so the doors appear set back in the chamfer).
Here i had two options:
1) use mason's mitres to make the frame joinery easier but then have trouble cutting the chamfers (I couldn't just whiz them on the band saw with a mason's mitre).
2) use 'normal' mitres for the frame, complicating construction of the frame but meaning that the chamfers would be easy to do.
I chose option 2. I cut the chamfers on all the face pieces on the bandsaw.
I then started to cut the mitres on my chop saw. They were rubbish. The cut wasn't square or accurate, I think the blade wasn't thick enough to resist wandering. Or maybe there was too much play in the saw. Either way they were poor. Onto the sliding table of the table saw. Rubbish again, this is a far east saw and, while it is excellent as a rip saw, the sliding table has so much play (that i've spent hours trying to correct) that its useless for cross-cutting.
In the end i had to make a mitre jig which ran along the rip fence. This was simply a sheet of MDF about 18" by 24" with a solid fence screwed and glued at 45 degrees. As i had thoughtlessly already cut the chamfers i needed to make L and R hand versions.
Success at last!
The mitres were clamped up and drilled and pinned from the top and bottom with dowels, two per joint. The dowel/holes will be hidden by the plinth and top.
The glue up of the face went swimmingly.
The glue up of the back and sides went swimmingly...
....except that when the mitred face was attached to the rest of the frame, the mitres opened overnight (creating 0.5 - 1 mm gaps on three of the four corners). I believe this was due to the use of softwood dowels which simply couldn't resist the stresses of the frame.
I'm not sure of a better way to do this without more complicated joinery. Biscuits? Hidden screws even? Anyway lesson learnt!
I was pretty gutted. In the end i had to handsaw out the mitres to an even and regular gap and add shims. I was disappointed but to be fair i'm sure maybe 1 out of 10 people would ever notice and only a few of them would care. The shelves and plinth were 19 mm MDF lipped with solid. The legs, apron and top were all solid.
As an experiment, and to avoid using a stain i decided to fume the oak.
I made a frame from cheap 44 x 20 mm battens and covered it in a giant plastic bag from a bed that had just been delivered along with lots and lots of gaffer tape. I poured some household ammonia into a baking tray and slid it inside. I was worried that my weak ammonia wouldn't be effective but i was too scared to use industrial stuff! I was pretty careful with the household stuff but the smell was by no means excessive and in the end i was worrying about gasing myself for no reason.
I left the cabinet in for about 24 hours. I took a breath, ripped open the plastic, poured the ammonia into an old plastic tub and put the lid on. I then left the workshop for a couple of hours! The cabinet had a unattractive gray/brown tinge when removed but a quick wipe with white spirit showed a lovely rich brown colour. The cabinet was finished with a few coats of shellac to give an open grained low-gloss finish.
Photo by Phil Faulks (wild7.co.uk)... i'm not sure about the white background, would just a sheet look more natural?
