Making a cabinet deeper ( dowel joints?)

[Tigercubrider]

I have two ikea Billy shelf units that a mate gave me- they match existing ones that I have
I would like to make a single cabinet that is a bit deeper than the standard size.
I have already cut down both units in height but will need to run two end panels down a table saw so that I have a pair of pieces around 20-25 cm deep that I can add to the back edges of the uncut ones to create a deeper unit.

How well would a dowel joint hold the edge to edge join? I would dowel maybe every 10cm and glue, using clamps to hold it all together while gluing. Once they are done, I would need to make 2/3 horizontal versions to be top/mid/base.

What glue? Normally I just use PVA
The material is chipboard
Ta

 

[Deleted member 174758]

Fluted beech dowels (8mm) at maybe 96mm or 128mm centres (that's because I like to work in "System 32" and it's how my dowel jig is set-up - 100 to 125mm would be fine) would be better than 250mm as you are sure to find the the boards won't marry properly at 250mm drilling centres. Ordinary PVA will do the job, in both the glue holes and spread on both the mating faces as the chipboard core can be quite "thirsty". You'll need to cramp well and ideally use cauls to even the clamping pressure out. Knock-over cramps can be made from 2 x 1in PSE softwood and screws. I have to say not my favourite way of doing this as the joints always show - I think it would be better to make-up new, wider uprights and drawers from scratch using pre-banded MFC - but doable with care.

Assume you are going to be re-using the drilled rear edges from elsewhere so that you can re-use the cam and dowel joiners and their holes

 

[Notch7]

Avoid dowelling unless you can be sure of high accuracy in the hole positions, within 0.5mm

 

[foxhole]

Just use a bit if chewing gum , will last longer than Ikea cwap.

 

[endecotp]

Avoid dowelling unless you can be sure of high accuracy in the hole positions, within 0.5mm

If you don’t have a fancy jig, you csn drill the holes in one piece, fit center points, press up against the other piece, and drill where the marks are.
https://www.axminster.co.uk/faithfull-dowel-centre-points-ax911311

 

[Tigercubrider]

Thanks
I have a jig on order from screwfix.
As I have cut down 2x 2m cupboard to 1m, I have spare wood to do some trials on
The intention is to use a table saw to reduce both parts of a side, so that the horizontal shelf joins do not coincide with the verticals
Due to the height being lower than eye level I can add a couple of metal plates.
I can also use ply/mdf as a back that is more structural than ikea' stuff

To be honest, I think that ikea stuff is well built and designed for the money
It will never be on antiques roadshow mind you

 

[big-all]

whilst i fully support the recycle ethos and the give it go as a good learning experience
sometimes the work involved and the predictable weak points make it probably not worth the trouble

 

[Tigercubrider]

Yeah,
If it didn't match the existing finish or was available in a larger size, I wouldn't bother but I can potter about with this

 

[big-all]

i love recycling old timber
i made my brother loads off matching computer and lever folder storage cupboards because off the six year book keeping requirement made them about 18 years ago from 2x1" frames infill with txg cladding and with solid fronted drawers
adapted mixed and matched about 30% off the cabinets to comply with greatly reduced virtually no paper storage required now
with half the rest and 20% new 2x1"planed made a play lid and coffee table sized storage cupboard with all recycled txg and some old 2x1"
you now have the sides and doors back and front with a white frame and nutty brown pine giving a brilliant contrast for his new grandson to add even more carricter and dents to as he plays