I have done a fair amount of metal casting, but never tried to build my own furnace, but I think your version is just too small and doesn't get hot enough.
1	I	I	PRON	PRP	Case=Nom|Number=Sing|Person=1|PronType=Prs	3	nsubj	3:nsubj|13:nsubj|15:nsubj:xsubj	_
2	have	have	AUX	VBP	Mood=Ind|Number=Sing|Person=1|Tense=Pres|VerbForm=Fin	3	aux	3:aux	_
3	done	do	VERB	VBN	Tense=Past|VerbForm=Part	0	root	0:root	_
4	a	a	DET	DT	Definite=Ind|PronType=Art	6	det	6:det	_
5	fair	fair	ADJ	JJ	Degree=Pos	6	amod	6:amod	_
6	amount	amount	NOUN	NN	Number=Sing	3	obj	3:obj	_
7	of	of	ADP	IN	_	9	case	9:case	_
8	metal	metal	NOUN	NN	Number=Sing	9	compound	9:compound	_
9	casting	casting	NOUN	NN	Number=Sing	6	nmod	6:nmod:of	SpaceAfter=No
10	,	,	PUNCT	,	_	13	punct	13:punct	_
11	but	but	CCONJ	CC	_	13	cc	13:cc	_
12	never	never	ADV	RB	_	13	advmod	13:advmod	_
13	tried	try	VERB	VBN	Tense=Past|VerbForm=Part	3	conj	3:conj:but	_
14	to	to	PART	TO	_	15	mark	15:mark	_
15	build	build	VERB	VB	VerbForm=Inf	13	xcomp	13:xcomp	_
16	my	my	PRON	PRP$	Case=Gen|Number=Sing|Person=1|Poss=Yes|PronType=Prs	18	nmod:poss	18:nmod:poss	_
17	own	own	ADJ	JJ	Degree=Pos	18	amod	18:amod	_
18	furnace	furnace	NOUN	NN	Number=Sing	15	obj	15:obj	SpaceAfter=No
19	,	,	PUNCT	,	_	22	punct	22:punct	_
20	but	but	CCONJ	CC	_	22	cc	22:cc	_
21	I	I	PRON	PRP	Case=Nom|Number=Sing|Person=1|PronType=Prs	22	nsubj	22:nsubj	_
22	think	think	VERB	VBP	Mood=Ind|Number=Sing|Person=1|Tense=Pres|VerbForm=Fin	3	conj	3:conj:but	_
23	your	your	PRON	PRP$	Case=Gen|Person=2|Poss=Yes|PronType=Prs	24	nmod:poss	24:nmod:poss	_
24	version	version	NOUN	NN	Number=Sing	28	nsubj	28:nsubj|32:nsubj|33:nsubj:xsubj	_
25	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	28	cop	28:cop	_
26	just	just	ADV	RB	_	28	advmod	28:advmod	_
27	too	too	ADV	RB	_	28	advmod	28:advmod	_
28	small	small	ADJ	JJ	Degree=Pos	22	ccomp	22:ccomp	_
29	and	and	CCONJ	CC	_	32	cc	32:cc	_
30-31	doesn't	_	_	_	_	_	_	_	_
30	does	do	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	32	aux	32:aux	_
31	n't	not	PART	RB	_	32	advmod	32:advmod	_
32	get	get	VERB	VB	VerbForm=Inf	28	conj	22:ccomp|28:conj:and	_
33	hot	hot	ADJ	JJ	Degree=Pos	32	xcomp	32:xcomp	_
34	enough	enough	ADV	RB	_	33	advmod	33:advmod	SpaceAfter=No
35	.	.	PUNCT	.	_	3	punct	3:punct	_
